Guardiola said in April that the 32-year-old Walker "cannot play" in the team's current system.

"Did it hurt? Of course it did. I can't lie and say it didn't hurt. You start to doubt yourself," Walker said.

After being dropped for the Bournemouth match, Walker was left out of three of the next four Premier League games.

He was also on the bench for Champions League matches against RB Leipzig and Bayern Munich as City hit the form that has carried them to the brink of a fifth title in six years and four wins away from an historic Treble.

By contract, John Stones has excelled in Guardiola's newly created inverted full-back role.

"Sometimes, you don't always agree with certain opinions in football but what he has done for me and for Man City in the last six years has been nothing short of tremendous," Walker said.

"He is my boss and I am one of the captains. I needed to make sure my disappointment isn't shown on the team."

It was Nathan Ake's hamstring injury that offered Walker a way back, with Guardiola forced to play Manuel Akanji at left-back and Stones alongside Ruben Dias in the centre.

Walker has responded with a series of impressive performances and came out on top in a memorable battle with Real Madrid dangerman Vinicius Jr in the first-leg of their Champions League semi-final the Bernabeu last week.

Vinicius Jr scored Real's goal in the 1-1 draw, with the second leg on Wednesday.

"I had to react as a professional," Walker added.

"I had to go back to basics, to what I am good at and what he bought me for and prove him wrong. That is what I have done."