Foden struck for the 2-0 win on the day.
Walker said: "Phil [Foden] has been class," he said. I think whenever people write him off, he always comes back and proves them wrong.
"You have to understand he is still very young, he's still learning and he's still going to have a lot of fire in his belly to prove the manager wrong.
"As long as he keeps putting in performances like he has done since the start of the season then he can't be dropped, but I'm not the manager and I don't make the decisions.
"When they have a low block, you have to move them and find gaps. I've set it back to Phil and you need them goals to settle the nerves when it is going to be a difficult game.
"We showed grit and determination to get the points. The clean sheet is important. We have let a couple of sloppy goals in recently. But I think the lads dug in today and showed just how determined we are to achieve great things this year."