A little over 24 hours after the club announced they had agreed a deal with Borussia Dortmund to trigger the Norwegian striker's €60 million release clause, De Bruyne scored four times in an hour at Molineux. City's 5-1 win over Wolverhampton Wanderers on Wednesday keeps Liverpool at arm's length in the title race and means Pep Guardiola's side need just four points from their final two games to be sure of the trophy.
They travel to West Ham United this weekend, while Liverpool face Chelsea in the FA Cup final, and by the time Jurgen Klopp's team play again in the Premier League, they could be six points adrift and with an inferior goal difference. Guardiola won't admit it but it's time to put the champagne on ice after a sparkling performance from De Bruyne.
"What can I say?" said Guardiola when asked about De Bruyne's performance. "I am very pleased for him, scoring four goals in the decisive part of the league. I'm so pleased for the performance and the result and the goals.
"We could have scored much, much more. It was a brilliant performance from all the players. All of them. Important victory. We need four more points to be champions and we will try and reach the first three on Sunday.
"It was important to arrive in the last two games with it in our hands. We still have a job to do, Liverpool is going to do the six points, 100%, so we have to do our four."
Haaland has got everyone talking about how good City could become in the future, but the present isn't bad either. Central to that is De Bruyne, who dismantled Wolves in a blistering display that will have had Klopp and his Liverpool players turning off their televisions before half an hour was on the clock. His first was a crisp finish with his left foot that skidded Jose Sa and into the far corner. His second hit the roof of the net after he followed in his own pass that nearly set up a chance for Raheem Sterling.
It was his third that was the best of the lot, with him squeezing between two Wolves defenders 25 yards from goal before skipping forward and arrowing another left-foot strike into the bottom corner before a fourth from close range in the second half. His first three goals all came within 24 minutes of kick-off to make it the third fastest hat trick from the start of the game after Sadio Mane in 2015 and Dwight Yorke in 2001.
On completing his hat trick, De Bruyne -- who also hit the post -- raced over to the City fans in the corner and replicated Haaland's meditation goal celebration.
The 21-year-old's impending arrival might have a few City attackers worried for their place, but the Belgian midfielder won't be one of them. He's now got 19 goals in all competitions, his best return for a single season. He will be expected to lay on plenty of goals for Haaland next season, but he's found his own shooting boots at the right time this season.
Since the beginning of March, he's found the net 11 times to help City close in on a fourth title in five years. Haaland will arrive at the Etihad Stadium in the summer keen to fulfil his undoubted promise and become one of the best players in the world. De Bruyne, though, is already there.
"I am disappointed for him because he missed the fifth goal and hit the post," Guardiola said jokingly. "The second part of the league was beyond perfect.
"He is so generous he has the sense to make an assist, but this season he also has the sense to score goals. He has been scoring decisive goals, against Chelsea, Liverpool and Real Madrid.
"We spoke during the years, you have to arrive to the box, to be close to the box and to score. This is the year he has done better and better. I have the feeling now he is starting to enjoy scoring goals."
Since the heartbreaking Champions League defeat to Real Madrid, City have responded with two wins from two, 10 goals scored and one conceded.
For Guardiola, the only downside was watching his injury problems at the back worsen after Aymeric Laporte and Fernandinho were both forced off in the second half. Kyle Walker, Ruben Dias and John Stones have already been ruled out for the final two games against West Ham, and Aston Villa and City ended the game at Molineux with Rodri and a half-fit Nathan Ake at centre-back.
Guardiola said afterward it will be "difficult" for either Laporte or Fernandinho to be fit to face West Ham on Sunday, but while City might be limping toward the finish line, another Premier League title is in sight.