The full-back moved to City from Tottenham in the summer of 2017 for a fee of around £50m, which was a world record high for a defender at the time.
The 31-year-old has since won three Premier League titles, four EFL Cups and an FA Cup under Guardiola, amid the very real prospect he could add to that run this season.
Even despite signing Joao Cancelo in 2019, Walker continues to be City’s first-choice right-back, with the Portuguese now widely deployed on the left.
In total, the England international made 213 appearances for one of Europe’s leading clubs in a period in which he largely dominated the domestic scene.
Speaking ahead of City’s Champions League quarter-final clash with Atletico Madrid on Wednesday, Guardiola praised Walker, believing the decision to spend such a sum on him was justified.
“He is so consistent and year after year he puts in great performances,” said the City boss.
“He was one of City’s greatest signings in modern history because he rarely gets injured and he always performs well.”