Hard as he tried to duck it, the issue of Louis van Gaal’s notoriously frosty relationship with Ronald Koeman would not go away. Van Gaal stonewalled, he bristled. He even offered up some grudging respect to his former assistant in an attempt to change the subject. But nothing could alter the fact that when Manchester United go to Southampton on Monday night, all eyes will be on the feuding Dutch duo. Intriguingly, Koeman is one point and one place ahead of his rival going into their clash at St Mary’s. VIDEO Scroll down for Louis van Gaal: My relationship with Koeman is private . Manchester United's Louis van Gaal refused to discuss his relationship with Southampton's Ronald Koeman . Koeman (pictured) and Van Gaal have had a frosty relationship for over 10 years since they worked at Ajax . ‘I don’t have to describe my relationship with the trainer of the opponent,’ said the United boss. ‘That’s more private I think. We play against Southampton and we have to speak about Southampton and not the trainer-coach.’ The two had clashed as players but their managerial fallout dates back to Van Gaal’s arrival at Ajax as technical director 10 years ago when Koeman was head coach at the club. Koeman objected to Van Gaal pulling up a chair in training and observing the session in the overbearing manner of a schoolmaster. In turn, Van Gaal felt Koeman was ‘weak’ in his handling of star players such as Zlatan Ibrahimovic, and blamed the coach for undermining him when he was ousted from the job a year later. Two men who had previously worked well at Barcelona, and whose wives Truus and Bartina had become best friends in Spain, were no longer on speaking terms. Van Gaal (right) and Koeman had run-ins with one another during their playing days in Holland . The pair worked well together though at Barcelona when Koeman (right) became Van Gaal's assistant . Their relationship changed when  working at Ajax, where they brought a young Filipe Luis to Amsterdam . The pair’s feud began when Van Gaal was appointed technical director of Koeman’s Ajax side in 2004. Koeman took issue with the way Van Gaal would get involved in training sessions, and Van Gaal labelled his compatriot ‘weak’ and felt the need to step in to break up a fight between team-mates Zlatan Ibrahimovic and Rafael van der Vaart during one of Koeman’s sessions. On the last day of the summer transfer window in 2004, Van Gaal accepted a bid from Juventus for Ibrahimovic, which angered Koeman, who had no time to sign someone to replace him before the window shut. Van Gaal claimed Koeman ‘engineered his departure from Ajax’ that same year, and declared: ‘I’ll never have dinner with Koeman again’. But Koeman insists: ‘That is his story. My story is different’. In a 2014 biography Van Gaal rekindled the bitter rivalry, stating: ‘The real problem at Ajax was Koeman no longer had control over the group (at Ajax). In principle, Koeman should have solved that, but he couldn’t.’ When Koeman later succeeded Van Gaal at AZ Alkmaar, the latter suggested that his replacement was third-choice on the club’s list. More recently, it has been claimed that Van Gaal took great delight in building a more expensive villa than Koeman’s in the Portuguese resort where they are sometimes neighbours. The United manager could not help but point to the difference in size and stature of their clubs yesterday when asked about the impressive job Koeman and his brother Erwin, Southampton’s assistant, have done on the south coast despite joining a club that had just offloaded some of their best players in the summer. United signed one of them, Luke Shaw for £28million, and were linked with Adam Lallana who ended up at Liverpool with Rickie Lambert and Dejan Lovren. ‘Southampton have a very good squad,’ said Van Gaal. ‘I know a lot of players and a lot of players were offered to us. But when Manchester United is coming, clubs are always asking more money and we have to pay because we are United. ‘Do you think Southampton pay too much for players? I don’t think so, because they are Southampton. There is always a relationship between Real Madrid and Manchester United and teams like Aston Villa and Southampton.’ On reports that United are set to spend upwards of £100m to continue overhauling the squad the manager added: ‘I think it’s disgusting always writing about numbers. It’s disrespectful to my players.’ And when asked about the depleted squad Koeman inherited, Van Gaal turned the question around. ‘I have heard that in the media,’ he added. ‘Do you know how many players we lost? I have never read that. We have lost more players but Ronald Koeman is a very good coach and I know he can do it. It’s always surprising that a club like Southampton are in that position but that’s a matter of coach, players and staff and when you do that it’s very good. They are able to finish in the top four but that’s also because I believe in the management of Ronald Koeman and his brother. When the cohesion is good he can manage.’ United have Wayne Rooney (left) available for Monday's clash but Southampton will be without Jack Cork . Van Gaal will make the trip to St Mary’s with his captain Wayne Rooney after confirming that the England striker has recovered from the knee injury that kept him out of Wednesday’s win over Stoke at Old Trafford. Southampton’s midfield options are becoming stretched, with Jack Cork facing at least six weeks on the sidelines. The 25-year-old will not play again this year after sustaining ankle-ligament damage in the Wednesday’s late 1-0 defeat at Arsenal. Cork’s absence compounds an increasingly tough situation for the Saints in central midfield, with James Ward-Prowse and Morgan Schneiderlin also out of contention for Monday’s match with United. Toby Alderweireld has helped fill the void in the past two matches but he is a doubt with a hamstring injury. Koeman said: ‘Jack Cork has ankle-ligament damage and he will be out for maybe more than six weeks. Toby has fatigue in his muscle and is doubtful.’ The injuries mean 19-year-old Harrison Reed could make his first Premier League start alongside the likes of Victor Wanyama and Steven Davis. ‘He is ready,’ said Koeman. ‘He’s a young player and he has to develop himself, but I’m a manager at a club that likes to develop young players.’ Toby Alderweireld (left) is also a doubt for the Saints with a hamstring injury suffered against Arsenal .
Southampton host Manchester United in Monday Premier League's clash .
Manchester United boss Louis van Gaal and his Southampton counterpart Ronald Koeman have had a simmering feud for over 10 years .
The pair's issues date back to when Van Gaal was technical director at Ajax and Koeman was manager .
Hard as he tried to duck it, the issue of Louis van Gaal’s notoriously frosty relationship with Ronald Koeman would not go away. Van Gaal stonewalled, he bristled. He even offered up some grudging respect to his former assistant in an attempt to change the subject. But nothing could alter the fact that when Manchester United go to Southampton on Monday night, all eyes will be on the feuding Dutch duo. Intriguingly, Koeman is one point and one place ahead of his rival going into their clash at St Mary’s. VIDEO Scroll down for Louis van Gaal: My relationship with Koeman is private . Manchester United's Louis van Gaal refused to discuss his relationship with Southampton's Ronald Koeman . Koeman (pictured) and Van Gaal have had a frosty relationship for over 10 years since they worked at Ajax . ‘I don’t have to describe my relationship with the trainer of the opponent,’ said the United boss. ‘That’s more private I think. We play against Southampton and we have to speak about Southampton and not the trainer-coach.’ The two had clashed as players but their managerial fallout dates back to Van Gaal’s arrival at Ajax as technical director 10 years ago when Koeman was head coach at the club. Koeman objected to Van Gaal pulling up a chair in training and observing the session in the overbearing manner of a schoolmaster. In turn, Van Gaal felt Koeman was ‘weak’ in his handling of star players such as Zlatan Ibrahimovic, and blamed the coach for undermining him when he was ousted from the job a year later. Two men who had previously worked well at Barcelona, and whose wives Truus and Bartina had become best friends in Spain, were no longer on speaking terms. Van Gaal (right) and Koeman had run-ins with one another during their playing days in Holland . The pair worked well together though at Barcelona when Koeman (right) became Van Gaal's assistant . Their relationship changed when  working at Ajax, where they brought a young Filipe Luis to Amsterdam . The pair’s feud began when Van Gaal was appointed technical director of Koeman’s Ajax side in 2004. Koeman took issue with the way Van Gaal would get involved in training sessions, and Van Gaal labelled his compatriot ‘weak’ and felt the need to step in to break up a fight between team-mates Zlatan Ibrahimovic and Rafael van der Vaart during one of Koeman’s sessions. On the last day of the summer transfer window in 2004, Van Gaal accepted a bid from Juventus for Ibrahimovic, which angered Koeman, who had no time to sign someone to replace him before the window shut. Van Gaal claimed Koeman ‘engineered his departure from Ajax’ that same year, and declared: ‘I’ll never have dinner with Koeman again’. But Koeman insists: ‘That is his story. My story is different’. In a 2014 biography Van Gaal rekindled the bitter rivalry, stating: ‘The real problem at Ajax was Koeman no longer had control over the group (at Ajax). In principle, Koeman should have solved that, but he couldn’t.’ When Koeman later succeeded Van Gaal at AZ Alkmaar, the latter suggested that his replacement was third-choice on the club’s list. More recently, it has been claimed that Van Gaal took great delight in building a more expensive villa than Koeman’s in the Portuguese resort where they are sometimes neighbours. The United manager could not help but point to the difference in size and stature of their clubs yesterday when asked about the impressive job Koeman and his brother Erwin, Southampton’s assistant, have done on the south coast despite joining a club that had just offloaded some of their best players in the summer. United signed one of them, Luke Shaw for £28million, and were linked with Adam Lallana who ended up at Liverpool with Rickie Lambert and Dejan Lovren. ‘Southampton have a very good squad,’ said Van Gaal. ‘I know a lot of players and a lot of players were offered to us. But when Manchester United is coming, clubs are always asking more money and we have to pay because we are United. ‘Do you think Southampton pay too much for players? I don’t think so, because they are Southampton. There is always a relationship between Real Madrid and Manchester United and teams like Aston Villa and Southampton.’ On reports that United are set to spend upwards of £100m to continue overhauling the squad the manager added: ‘I think it’s disgusting always writing about numbers. It’s disrespectful to my players.’ And when asked about the depleted squad Koeman inherited, Van Gaal turned the question around. ‘I have heard that in the media,’ he added. ‘Do you know how many players we lost? I have never read that. We have lost more players but Ronald Koeman is a very good coach and I know he can do it. It’s always surprising that a club like Southampton are in that position but that’s a matter of coach, players and staff and when you do that it’s very good. They are able to finish in the top four but that’s also because I believe in the management of Ronald Koeman and his brother. When the cohesion is good he can manage.’ United have Wayne Rooney (left) available for Monday's clash but Southampton will be without Jack Cork . Van Gaal will make the trip to St Mary’s with his captain Wayne Rooney after confirming that the England striker has recovered from the knee injury that kept him out of Wednesday’s win over Stoke at Old Trafford. Southampton’s midfield options are becoming stretched, with Jack Cork facing at least six weeks on the sidelines. The 25-year-old will not play again this year after sustaining ankle-ligament damage in the Wednesday’s late 1-0 defeat at Arsenal. Cork’s absence compounds an increasingly tough situation for the Saints in central midfield, with James Ward-Prowse and Morgan Schneiderlin also out of contention for Monday’s match with United. Toby Alderweireld has helped fill the void in the past two matches but he is a doubt with a hamstring injury. Koeman said: ‘Jack Cork has ankle-ligament damage and he will be out for maybe more than six weeks. Toby has fatigue in his muscle and is doubtful.’ The injuries mean 19-year-old Harrison Reed could make his first Premier League start alongside the likes of Victor Wanyama and Steven Davis. ‘He is ready,’ said Koeman. ‘He’s a young player and he has to develop himself, but I’m a manager at a club that likes to develop young players.’ Toby Alderweireld (left) is also a doubt for the Saints with a hamstring injury suffered against Arsenal .
is private . Manchester United's Louis van Gaal and Van Gaal have had a frosty relationship for over 10 years since they worked at Ajax . ‘I trainer of the opponent,’ said the United boss. as technical director 10 years ago when Koeman a young Filipe Luis to Amsterdam . The pair’s feud began when Van Gaal was appointed technical in the management of Ronald Koeman and his