Alexis Sanchez has made a blistering start to life at Arsenal, racking up 18 goals, 10 assists and countless plaudits in his first few months in England. The Chilean's work-rate, creativity and finishing mean he's a firm favourite with fans at the Emirates Stadium as well as one of the first names on Arsene Wenger's team sheet. But his form has tailed off in recent weeks, with Sanchez failing to find the net in February, and the former Barcelona star has now gone seven games without a goal. Alexis Sanchez has been suffering a bit of a drought since Mesut Ozil returned to fitness . Sanchez has not scored a goal for Arsenal in his last seven games, providing just one assist in that time . The Gunners forward has been vital to their form this season, but does not look at his best at the moment . A hamstring injury, which ruled Sanchez out of games against Aston Villa and Tottenham, seemed to stall his season, but there are also concerns about the 26-year-old's role in the team since the return from injury of Mesut Ozil. Gunners fans had hoped that when Ozil and Sanchez, Arsenal's two most expensive players ever, played together, Wenger's side would find another gear. But it appears the two struggle to play together. Sanchez has not scored a goal with Ozil on the pitch since October 1, and the Gunners win percentage with their two stars playing together is worryingly far lower than when one is absent. While results have picked up since the German's return from injury, the impact on Sanchez's performances is a concern. The Chilean's barren spell has coincided with Ozil's comeback, and a move away from the central role in which he was excelling. Sanchez celebrates scoring against Stoke City in early January, his last goal for the club . The Chilean has scored 18 times since his move from Barcelona, but none since January 11 . Sanchez celebrates after scoring against Manchester City, but he generally struggles when Ozil plays . In the World Cup-winning playmaker's absence, Sanchez had been operating as Arsenal's No 10, with a license to drift all over the pitch and run at the defence. But Ozil has slotted into that role, with great effect, shunting Arsenal's best player this season out to the left wing. The effect has been devastating to Sanchez's game. In his first 30 appearances for Arsenal he created 74 chances, at a rate of almost two and a half per game. In his last seven, he averages around one and a half a game, with only one assist. It is a similar story with his shooting. His goalless run is the result of having just 13 shots in seven games, of which only five have been on target. Sanchez celebrates with Santi Cazorla, who has recently moved to a deep midfield role, to great effect . Sanchez has hit the buffers after storming start to his career in north London . Ozil has been in superb form since coming back from injury and slotting into the No 10 role . Ozil's playmaking, including both assists in a win over Everton, has spurred Arsenal onto a winning run . In fact he has managed a shot on target every 102 minutes, a poor return compared with the rest of the season, where he had worked the goalkeeper every 57 minutes. It is not just Sanchez's position that has changed with Ozil's return, but also the shape of the team. During Sanchez's best run of scoring form this season, when he notched six times in four games during October and November, the Gunners had two recognised central midfielders in the side. Early in the season that was usually Mathieu Flamini or Mikel Arteta in the holding role alongside Aaron Ramsey or Jack Wilshere, but Alex Oxlade-Chamberlain, Tomas Rosicky and of course the emerging Francis Coquelin have all been involved more recently. This gave Sanchez a platform, whether from the wing or a more central position, to focus on attacking. He always works hard off the ball, but he needed to worry less about his positioning defensively. Francis Coquelin's emergence as a quality holding midfielder has allowed Arsenal to change their system . Arsene Wenger has played Ozil in the middle, leaving Sanchez to help out in a lightweight midfield . Wenger needs to find a way of getting his two stars to play well together as Arsenal push for a top-four finish . Since Ozil returned, Santi Cazorla has moved into a deep-lying midfield role to glorious effect, freeing up Ozil to drift around the midfield picking his passing. Both men have benefited, and the Gunners have won seven of their last eight league games. But it has meant that Sanchez has had to be more disciplined, tracking back to help out in a light-weight midfield, and spending more time defending than when he was the main man. For now, it is a system that appears to be working - while Sanchez's stats falter, Arsenal have been in decent form since Ozil's return, the aberration against Monaco aside. But with the race for Champions League football hotting up, Wenger will want to start getting the best out of his superstar again, alongside - rather than instead of - Ozil.
Alexis Sanchez has not scored a goal for seven games . Mesut Ozil's return to fitness has seen Sanchez moved out to the wing . Arsenal's win percentage falls drastically when both their stars play . But system seems to be working, with seven wins from eight league games . Arsene Wenger's side take on QPR on Wednesday night .