The forward believes their fine counter-attacking display was key to the much-needed victory.
The veteran 'keeper was reinstated for the game against the German champions having been dropped for their losses to Dinamo Zagreb and Olympiacos, and showed why the decision to leave him out was a big mistake by manager Arsene Wenger.
The 'keeper was in fine form throughout the game as he made a number of big saves to keep the score at 0-0, with one particularly fine save to deny Robert Lewandowski sticking in the memory.
And Walcott was one of many to praise Cech for his display.
“Everyone did their jobs really well and I have to say Petr in goal was fantastic and made a number of very, very important saves,” he told arsenal.com.
“Everyone worked really hard and deserved it. There was a lot of pressure on us, we knew we couldn’t lose but a win was a massive ask. The confidence is just flowing through the team at the moment, you can see that.”
The forward also says that putting in a fine counter attacking display was key to their victories.
The Gunners spent large periods of the game without the ball as Pep Guardiola’s side maintained possession, but remained solid throughout to limit them to few clear-cut chances.
They then hit the in-form Bundesliga side on the break to score both of their goals and secure a 2-0 win, and Walcott says it was one of those days where they needed to be patient.
“It was just one of those days when we had to be patient,” he added.
“We knew we were not going to have a lot of the ball and we had to go at them on the counter-attack. We were getting at them while we could and dropping back while we had to and obviously the goals came at great stages.”