The defending champions then took control as De Bruyne teed up Haaland again and this time the Norwegian striker finished, before the Belgian added a fourth – marking his century of goals for City since joining in 2015 – with a ferocious first-time shot.
Substitute Odsonne Edouard slotted in a late consolation for Palace but this was another crucial victory for Guardiola’s side in an enthralling three-way title race.
City moved level on points with leaders Liverpool, who visit Manchester United on Sunday, while Arsenal face Brighton later on Saturday.
With one eye on Tuesday’s Champions League quarter-final tie against Real Madrid, Guardiola made four changes to the City side, with Phil Foden dropped to the bench just days after scoring a hat-trick in a 4-1 win over Aston Villa.
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But in came De Bruyne and Haaland – and both made their mark to fuel City’s charge for an unprecedented fourth successive league title.
Palace, still finding their feet under new boss Glasner, showed plenty of positive signs, particularly in the first half as their defensive resilience and organisation kept the visitors at bay.
They were boosted by the return of Michael Olise off the bench after missing seven games through injury, and the lively Edouard went close before he squeezed home a nice close-range finish four minutes from time.
“I’m not satisfied with the result but I saw many positive things in our performance,” said Glasner.
“When we lose 4-2, I don’t like to talk about positive things, but in phases of the game we could compete. It shows we are able to create chances – but of course when you concede four goals, you lose.”
City were too strong in the end and, while Guardiola was able to rest Foden and Bernardo Silva, De Bruyne stepped up to show his quality and claim his landmark goal after an injury-plagued season.
In another boost, defender John Stones managed to play the full match upon his return after being injured on England duty.
Palace have proved a tough opponent for City in the past – they came from 2-0 down to draw 2-2 at the Etihad in December – so this was a vital victory for Guardiola’s side to keep the pressure on Liverpool and Arsenal.
