Mikel Arteta's penalty proved enough for Arsenal to win 1-0 at Wigan on Saturday and make it three Premier League victories in a row for the first time since March.
There was very little between the sides and it was the hosts who had the best chance of the first half but it was wasted by Arouna Kone.
The three points lifted Arsenal up to third ahead of Chelsea, which plays Sunday, while Wigan remains in the bottom three and has now taken only one point from its past five games.
Gunners boss Arsene Wenger named the same team that defeated Reading 5-2 on Monday, with Walcott again given a chance to impress up front.
The Latics started with a flat back four but with McCarthy providing a shield in midfield, particularly against the skills of Monday's hat-trick hero Santi Cazorla.
Despite the rain, Arsenal had the first chance of the game in the ninth minute when Arteta was allowed time and space to drive forward and play in Alex Oxlade-Chamberlain on the right, but his shot was well saved at the near post by Ali Al Habsi.
The goalkeeper was making his 100th appearance for the Latics and he was called on again in the 11th minute to beat away a stinging shot from Lukas Podolski.
The frustration for the hosts was they could not turn possession into chances, with both Ronnie Stam and Beausejour having a crossing off day.
Wigan's pace up front certainly had the potential to trouble Arsenal, which was playing a high line, and Kone timed his run to perfection in the 24th minute to collect Franco Di Santo's through ball.
Emmerson Boyce was playing a captain's role in the absence of Caldwell and a shot from Walcott was one of many blocks.
Oxlade-Chamberlain had been quiet in the first half but he began the second in fine fashion and his pull-back set up Walcott for a shot from 10 yards that Al Habsi blocked with his arm.
It was a fine save from the Oman international but Walcott really should have scored.
The England international was the key man when Arsenal did break the deadlock after an hour, though, as Moss judged Walcott was pushed by Beausejour in the area.
It was a clumsy challenge by the Chile international and Arteta was coolness personified from the spot, sending Al Habsi the wrong way. Wigan needed firing up and the home fans' displeasure with Moss certainly achieved that.
Walcott was given his chance up front after impressing in the role against Reading, and Wenger gave the England man qualified praise.
"I wouldn't like to judge him on one game but he has the ingredients to play there," Wenger said. "He didn't have much service today, he was a bit isolated but he can always be decisive. Today again he made the decision and he got the penalty."
With 20 minutes to go, the Latics twice tested Szczesny, first Maynor Figueroa sending in a low skidding shot and then Kone drawing a block from the Pole after doing very well to cut in from the left. Szczesny was then a spectator a couple of minutes later as James McArthur set up David Jones on the edge of the box for a shot that flew just wide of the upright.
Stam finally found a decent cross in the 82nd minute, but it was stabbed clear by Mertesacker with Kone waiting for a tap-in, and two late appeals for handball in the area were turned down to complete a thoroughly frustrating afternoon for the hosts.Information from Press Association was used in this report.