The Gunners' wait for a trophy is in danger of extending to eight years after a 3-1 defeat at home to Bayern Munich left them on the brink of elimination from the Champions League.
"We've got the best man in the job to get our heads back to where they should be"
However, the former Southampton attacker has urged supporters to stand by the Frenchman, who he is sure will be able to lift the players' moral despite the devastating defeat.
"We've got the best man in the job to get our heads back to where they should be," he told reporters. "I've played a lot of games in the Champions League and I know how things go."
The Gunners currently sit fifth in the league table, four points behind rivals Tottenham and just two points ahead of Everton and Walcott admits it would be a huge blow if they were to miss out on Champions League qualification.
"If you are a top team, and with the saga of not winning anything for such a long time, it's always disappointing if that happens," the 23-year-old continued.
"But I don't want to focus on the negativity about that. I just want to focus on the positive side of the team, because I know how good those guys are, and get to where we should be."
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And the England international thinks conceding early and giving away sloppy goals is becoming an unwanted habit for Wenger's men, while they must build on a better second half in the away leg.
"It's happening most weeks," he added. "We didn't really have a slow start [against Bayern]. It was just sloppy goals – goals that could have been avoidable, I felt.
"We knew how strong [Bayern] were going to be. They're very well organised, they did their job, they took their chances which is the most important thing.
"We had a few but didn't manage to take it. In the Champions League you need to take limited opportunities, but, like I say [we've] got to take the positives out of the second half.
"There's a lot we can learn from that, learn from Bayern as well because we want to be like that."