Robin van Persie netted his first goal in four games when he dispatched a ninth-minute penalty after Sebastien Bassong was shown a straight red card for bringing down Theo Walcott in the box.
And Walcott then put the Gunners firmly in control just two minutes later with a cool right-footed finish after being found by Van Persie.
Yossi Benayoun added gloss to the score-line in the 69th minute with a well-taken finish to seal a victory that moves the Gunners five points clear of fourth-placed Tottenham Hotspur with five games left to play.
“I am very happy that we are in this position but I am also very cautious because some teams have been in that position before,” said Wenger after the match.
“We want to win our next game because where we have come from this season we must be focused. We have come from very deep and to stay in this position we have to focus on our next game.”
Van Persie took his tally for the season to 34 with his spot-kick – and Wenger, whose next face Wigan at The Emirates on Monday, heaped praise on the Dutchman after his prolific form in front of goal this season.
“I think he equalled the record of Ian Wright by scoring against 17 different teams in the Premier League out of 20,” he continued.
“That is absolutely remarkable in the modern game so I would like to congratulate him because that has never been done before. When your striker scores against 17 different teams, that is sensational.”
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