Arsenal manager Arsene Wenger has told his in-form side not to under-estimate strugglers Aston Villa in their Premier League clash at the Emirates Stadium on Sunday.

The Gunners produced arguably their best performance of the season to win 2-0 away to champions Manchester City in the league before the holders saw off Brighton in the fifth round of the FA Cup.

Arsenal could return to the top four, and a Champions League place, with a fifth straight win in all competitions if they see off goal-shy Villa.

But Wenger said the north London club could take nothing for granted on Sunday.

"We want complete focus and commitment to be completely concentrated on what we want to achieve," said Wenger.

"We have to be very cautious with the mood in our job because the swings are very quick," added the veteran French boss, who could be without influential Chile forward Alexis Sanchez because of a hamstring problem.

"You need a good balance between an optimistic mood and urgency as well.

"We are in a job where, of course, you want the level of concentration very high and that is what we want to achieve now.

"We go into a period in the next four months that will decide our season, so we have to be conscious that our commitment has to be 100 percent."

Villa are the lowest scorers in English football's top-flight, with a mere 11 goals from 22 games so far this season.

However, Wenger said: "There is a distortion between the quality Villa have going forward (and their goal tally).

"When you look at the names they have on their team sheet, they have (Christian) Benteke, (Gabriel) Agbonlahor and (Andreas) Weimann, who can all score goals.

"They suffered a lot from Agbonlahor's injury after Benteke was out for a long time.

"But when everybody's there, it is a team who look quite dangerous going forward."

Meanwhile Wenger said goalkeeper Wojciech Szczesny had reacted well to the challenge to his place that has come from Colombia's David Ospina.

Poland international Szczesny was between the posts against Brighton for the first time since the New Year's Day defeat at Southampton, after which he was reported to have been smoking in the showers.

But Wenger said: "He is 100 percent committed in training and works harder than ever.

"For me that is the most important when a player is questioned at some stage, how he responds shows you his strength of character, and on that front Wojciech has done extremely well until now.

"At the moment, the competition is there. I just always have to make the decision who plays the next game."