Arsene Wenger finally starts Cech in goal against United. While Young will start in right-back for Red Devils.
Arsene Wenger was criticised for starting Ospina in the UCL match against Olympiakos with the No. 2 goalie making a number of errors, notably dropping the ball behind his goal line.
Cech has been restored between the sticks, while an injury prone Coquelin starts in midfield. And Walcott replaces Giroud up front.
For United, Valencia has been punished for handing Wolfsburg a chance at goal, with Young starting at right back in his stead.
The only other change is Carrick starting for Depay, while Wilson is on the bench.
TEAM NEWS IN FULL:
Arsenal: Cech; Bellerin, Mertesacker, Gabriel, Monreal; Coquelin, Cazorla; Ramsey, Ozil, Alexis; Walcott. Subs: Ospina, Debuchy, Chambers, Gibbs, Oxlade-Chamberlain, Campbell, Giroud.
Manchester United: De Gea; Young, Smalling, Blind, Darmian; Schweinsteiger, Carrick; Mata, Rooney, Depay; Martial. Subs: Romero, Jones, McNair, Schneiderlin, Valencia, Fellaini, Wilson.