It marked his 350th game for the club.
Walcott told arsenal.com: "It was a great move and I'd like to get 10 more of those a season.
"They're nice, but I was in the right place at the right time and I was pleased with that. But like I say, I'm more pleased with the three points and we've obviously got a big game on Wednesday now. We've got to recover well, there's games coming thick and fast now and that's why I'm leaning against this wall right now!"