Leicester boss Claude Puel insisted there were no hard feelings about the way City went about landing the player after an injury to Leroy Sane forced their hand. But he and City again owed a lot to the irrepressible De Bruyne, who created his side's opening three goals in another outstanding display.
The Argentina worldwide now has 28 goals in all competitions this season - eight more than Raheem Sterling who also got on the scoresheet against the Foxes.
After a sluggish first half in front of a Premier League record crowd of 83,222 at Wembley, Kane jumped highest to head home his seventh derby goal in seven games and 23rd in the league this season.
However, Leicester have already proved that they are will not be easy to deal with in the transfer market and capable of hanging onto their stars, after they refused to let Riyad Mahrez move to Manchester City last month, despite an offer of £65m reportedly being on the table.
The day belonged to Aguero, though, and he rounded off the game with two superb strikes. Apparently not as the Argentine uncharacteristically lost the ball in the area, allowing Leicester to launch a counter-attack of their own. It's unclear whether or not he will be in contention, but if he is, then he'll certainly be looking to prove a point to Pep Guardiola.
"I wish he can come back as soon as possible and play, he's an extraordinary player and everyone enjoys watching the better players".
As we know, Aguero bagged a hat-trick and De Bruyne weighed in with a trio of assists, too.
One man who was more responsible than others for the defeat was Foxes goalkeeper Kasper Schmeichel. The Austrian defender, on loan from Bayer Leverkusen, was pleased with his contribution and the scores remained level. Aguero unleashed a rocket of a shot from just outside the box in the 90th minute to score his fourth goal of the second half. The likes of De Bruyne and Ilkay Gundogan were still given huge amounts of time on the ball by the Foxes, and that allowed them to pick simple passes to run the visitors ragged.
And the response to his inclusion has been mixed, with many Leicester fans praying their star can pay them back with a victor.
A neat exchange between Sterling and De Bruyne on the right flank allowed the latter to tease a low cross to gift Aguero a tap-in.