Arsenal manager Arsene Wenger has claimed that the criticism aimed at Hector Bellerin during Monday night's 3-0 defeat to Crystal Palace was unfair.

The 22-year-old full-back has rarely been called into question since breaking into the first team, but a number of fans berated his display during the loss at Selhurst Park as Arsenal fell to another damaging defeat.

Wenger acknowledged that the Spaniard has not been at his best since returning from an ankle injury, but urged the supporters to get behind the team rather than turning on them.

"He has not come back to his level since he has been injured. I think (he has been feeling the ankle) for a while. Then you get bad habits and you forget that your job first is to defend and win challenges because you protect yourself a little bit," he told reporters.

"Then you realise you have to come back and I think now he is trying to focus on again what is important, to defend well and after he can give us that extra bit that is important as well. I agree that for a while he was not the Hector Bellerin we had seen at the start of the season."

When asked whether the criticism at Palace was unfair, Wenger added: "I think, yes. He is a guy who is genuinely Arsenal and wants to do well. He is ready to play with pain and I think it is, yes.

"The fans want to be behind the team and the way we respond on the football pitch will decide the attitude of the fans. The fans love the club. It's a good period to be united and not divided. Historically Arsenal has been about that. One of our values is to be together. There's no better period of the season than to show it now."

Arsenal travel to Middlesbrough on Monday night having lost seven of their last 12 matches across all competitions, including five of their last six away from home.