The 24-year-old received a pass on the right edge of the box from Mikel Arteta before finishing after just 20 seconds for his 20th goal in all competitions this season for the Gunners.
|2/9||Arsenal are 2/9 with BetVictor to finish in the Premier League top four
Commenting on the goal, Wenger told the club's official website: "[Walcott] scored a bit of a similar goal to the one against Manchester United. It's a short backlift, he makes good runs and he's calm now in front of goal.
"He's more mature in his finishing. You certainly remember him when he arrived - in front of goal, the ball could go anywhere. Now you see every time he hits the target. He forces the keeper into a save. That's why his numbers are so much better."
The England international has on occasion played as the central striker in the Gunners' front three but has mostly started on the right flank and did so again beside Lukas Podolski, who started in the central role in place of the suspended Olivier Giroud.
Wenger explained: "I use him on the flank because I try to put a player in the middle who can score goals and having another one on the flank who can score goals gives you a little bit of security. We finished with him in the middle."