Shawcross was outstanding in victory over Liverpool.
"They made it difficult for us. We soaked up a lot of pressure and got a bit of luck along the way," said Walters.
"How Ryan's not getting called into the England squad I don't know.
"He played against Suarez and Andy Carroll and coped with everything they threw at him.
"The spirit within the camp is first class, we're all there for each other.
"We've won six and drawn two and it's been first class all the way through and yesterday epitomised us in the way we defended.
"We put bodies on the line and there was some great defending to keep a clean sheet.
"That is what we are all about and the new boys (Peter Crouch and Wilson Palacios both made their debuts while Cameron Jerome was an unused substitute) who have come in have taken that on board and carried it through."