With 60 years of managerial experience between them, Louis van Gaal and Arsene Wenger have more big match experience than most coaches still involved in European football. They have, as they saying goes, forgotten more about the game than many people will ever know. Games like this, however, still throw up unique questions and challenges, both before and during play, and on Monday night he two men faced one of their biggest nights of the season in a competition their respective clubs are unusually desperate to win. Here, Ian Ladyman assesses how they shaped up at Old Trafford. TEAM SELECTION . Managers are paid to make the right calls and sometimes that involves an element of risk. Wenger’s decision to include Danny Welbeck ahead of Olivier Giroud seemed baffling. Giroud had scored five goals in his last five games and it was hard to think Welbeck would have anything in his repertoire that his former team-mates in the United ranks didn’t know all about. For an hour here it seemed as though the Arsenal manager had blundered a little. Arsenal were familiarly quick and progressive through midfield but Welbeck seemed unable to hold of possession long enough to bring his supporting players Alexis Sanchez and Alex Oxlade Chamberlain in to play. Arsenal left back Nacho Monreal jumps in the air after putting his side in the lead . Manchester United captain Wayne Rooney cancelled out Nacho Monreal's opener . Ultimately, though, Wenger’s decision was vindicated when Welbeck was bright enough to anticipate Antonio Valencia’s back pass and calm enough to win his subsequent challenge with David de Gea and score the winner. For their part, it was surprising to see United without their best passer, Michael Carrick, but they still had a bold look about them at the start and that was indicative of the fact that this was a game Van Gaal wished to win at the first attempt. Daley Blind was selected as United’s only holding player and that, in turn, released Ander Herrera and Marouane Fellaini to try and hurt Arsenal further up the field. Most interesting, though, was Van Gaal’s decision to select Ashley Young as a traditional winger. Young has looked good going forward from left-back this season and by shunting him further up the field, Van Gaal gave him licence to trouble young Hector Bellerin. It was a plan that worked early on, as Bellerin was booked for a foul, but Young couldn’t maintain the threat and spent too much time in his own half. Ashley Young celebrates with Rooney following the Manchester United and England captain's equaliser . TACTICS AND STYLE . Wenger is nothing if not brave when it comes to these games and that was reflected in his decision to pair Santi Cazorla and Mesut Ozil as central players. Some Arsenal supporters may have wanted their team to look rather more secure and at times the visiting team did look vulnerable when Fellaini edge forwards to impose his unique brand of physicality on to the Arsenal central defenders. Arsenal’s three-man attacking formation took a while to click but the holders’ full-backs Bellerin and Nacho Monreal got significant change out of their opposite numbers, forcing them back, and this allowed the visiting team to stretch the play in a fashion that made United look distinctly uncomfortable. Santi Cazorla (second left) vies for the ball with United trio Young, Daley Blind and Marouane Fellaini . When United did have the ball it was clear they had been instructed to play with more urgency. Certainly Van Gaal’s team moved the ball more quickly early on and tried to deliver telling balls between two Arsenal central defenders that can be vulnerable, something that paid dividends when Wayne Rooney equalised. Unfortunately, this is not a United team that has any great confidence or belief and as soon as things started to go wrong their game plan fell apart to the extent that the final 20 minutes saw them launch a succession of long balls up towards Fellaini. That, it must be said, was startlingly unsophisticated. One final question, here: If Rooney is the man chosen to take your free-kicks from out wide, just what does that say for the abilities of Young and Angel di Maria? TECHNICAL AREA SAVVY . Wenger once got so animated here that he ended up standing on the platform behind the dug-outs after being sent from his seat. It was not a good look but then his team were on the brink of a defeat at the time so perhaps he was to be excused signs of madness. On Monday night he was visible at times and contributed a lovely 360 degree dance after the first goal. A place in Strictly Come Dancing beckons in retirement, perhaps. Van Gaal, meanwhile, rarely ventures from his seat and whether that is the right thing or not depends on whether you think footballers actually benefit from a frantic man in a suit screaming at them while they are trying to put in to practice the things they have spent all week rehearsing. As usual, Van Gaal spent much of the time sitting down whilst scribbling mysteriously on his big black clipboard. It will be some letter home by the time the season ends and, sadly for him, will not include any stories about Wembley. Arsene Wenger (left) was animated on the touchline during Arsenal's win against Manchester United . SUBSTITUTIONS . Van Gaal sees football as an 18-man game and his use of substitutes – both good and bad – has been a feature of his time at Old Trafford, just as it was during last summer’s World Cup. Here, the United manager saw his team very much in the game and gathering momentum towards the end of the first half but then made two changes during the interval. It is hard to say they worked, the hooking of Luke Shaw and Ander Herrera serving only to rob United of any impetus. Luke Shaw was taken off in the second half for United after proving to be ineffective on the left . Equally, the early subs left Van Gaal with no wild card as United chased the game late on. As a result, Radamel Falcao remained on the bench. Wenger, meanwhile, was prepared to wait a little longer but his hand was forced when Oxlade-Chamberlain was injured immediately after the interval. Wenger’s response was positive, sending on a like-for-like replacement in Aaron Ramsey. VERDICT . If you come away with a victory on a night like this then you win the duel, it’s as simple as that. Wenger gambled with his selection and tactics and knew he would be criticised if it didn’t come off. Managers are paid to make the decisive calls, however, and to the victor the spoils. Louis van Gaal (middle) issues instructions to United midfielder Ashley Young . The Frenchman points the way during his side's FA Cup quarter-final win against Manchester United .
Arsenal beat Manchester 2-1 in their FA Cup quarter-final clash on Monday . Danny Welbeck came back to haunt his former side with the winner for Arsene Wenger's men . Louis van Gaal's substitutes proved to be too defensive on the night . Whereas Arsene Wenger gambled with his tactics and reaped the rewards . Arsenal will play either Bradford or Reading in the semi finals .