The Gunners blew a 4-0 first-half lead to draw 4-4 at Newcastle United.
"When we landed at Luton, we all put on our phones and had a little check," revealed Walcott. "Everybody had grins on their faces. It changed the mood. It changed the boss' mood as well.
"He would have gone home thinking it was a point gained and something we can build on.
"The first half performance was the best I have been involved in.
"I watched it again on Match of the Day. I couldn't change the result and I didn't want to sulk. I wanted to see my goal as well."