Mourinho came into the match claiming he would field a weakened team but the line up did not seem to suggest so. The only guaranteed starters who missed out were Eric Bailly, Paul Pogba and Marcus Rashford as the likes of Chris Smalling, Henrikh Mkhitaryan, Micheal Carrick, Ander Herrera and Anthony Martial all starting.
The first half saw few chances with Welbeck missing a goodchance after being fed by Ozil while Martial could not profit from a defensive mix-up. Arsenal scored through the impressive Granit Xhaka whose long range effort deflected off Ander Herrera.
Three minutes later Welbeck scored a header after connecting with a right wing cross from the industrious Alex Oxlade-Chamberlain.
The victory was Wenger’s first over Mourinho in a Premier League game from the Portuguese time at Chelsea and Manchester United. Arsenal are now two points behind United and six adrift of Manchester City, but still have a game in hand on both.