Alexis Sanchez will start for Arsenal tonight as they welcome Southampton to the Emirates.
Gunners manager Arsene Wenger has named an attacking lineup as he seeks revenge for their 4-0 defeat at St Mary's on Boxing Day, with the Chilean sitting alongside Mesut Ozil, Olivier Giroud and Joel Campbell as Theo Walcott drops to the bench.
There is only one other change from the side that were defeated by Chelsea nine days ago, with Mertesacker relegated to the bench in favour of Gabriel Paulista.
Mathieu Flamini retains his place alongside Aaron Ramsey in Wenger's starting XI ahead of the fit-again Francis Coquelin, who starts among the substitutes.
Mohamed Elneny, who impressed during his Arsenal debut against Burnley in the FA Cup on Saturday, plays no part in the matchday squad.
The visiting Saints must make do without the services of Charlie Austin, who had a dream debut with a winner at Old Trafford last time out, after he picked up a knock in training.
Manager Ronald Koeman makes two changes from the side that triumphed over Manchester United, with Oriol Romeu and James Ward-Prowse coming into the middle of the park in place of Matt Targett and Jordy Clasie.
Arsenal: Cech; Bellerin, Gabriel, Koscielny, Monreal; Flamini, Ramsey; Campbell, Ozil, Sanchez; Giroud
Subs: Ospina, Gibbs, Mertesacker, Chambers, Coquelin, Oxlade-Chamberlain, Walcott
Southampton: Forster; Cedric, Fonte, Van Dijk, Bertrand; Long, Romeu, Ward-Prowse, Mane, Tadic, Wanyama
Subs: Stekelenburg, Yoshida, Clasie, Martina, Pelle, Juanmi, Targett
Follow live coverage of the match from the Emirates with Sports Mole's text commentary here.