Can a player be 'back' after just one game?
Ilkay Gundogan's recent struggles after returning from injury after a false dawn at Watford provide evidence against it, but Kevin De Bruyne made a compelling case on his first Premier League start since playing at United before the November international break.
The second goal was obviously straight out of the De Bruyne textbook, those moments where he looks like he is tired of pretending to be playing the same game as everybody else and decides to end the charade by blasting the ball into the back of the net without even trying.
His first, though, will have pleased Pep Guardiola even more.
The ball from Rodri deserves more than just a word because it was sensational, the sort of ball that would instantly have had the nation salivating if De Bruyne himself had played it. It fizzed along the floor vertically up the pitch, with so much power that it looked like it would go beyond everyone before tantalisingly holding up as the Belgian raced onto it.
He did race, though, and that was the point.
For the first time in ages, De Bruyne looked sharp in body and mind in everything he did. Rather than moves breaking down when they got to his feet, he was sparking play by outwitting and outclassing any opponents that came his way.
De Bruyne is in the running for our Fans' Footballer of the Year award - you can vote for him here.
It is hard to know just how long this renaissance will last because of how little resistance Leeds were able to put up. A team that Guardiola had bigged up before the game - calling them one of the best teams in the Premier League in his programme notes - were passengers from the first whistle and looked shellshocked as the goals flew in; keeper Illan Meslier was probably their best player in a 7-0 defeat.
That is an issue for another day, though.
Guardiola is not short of positives to take away from City's biggest win since they thrashed Watford 8-0 in the Premier League back in September 2019. Phil Foden looked sharp again, Jack Grealish got a confidence boost by scoring his first headed goal in the Premier League and Nathan Ake and Fernandinho got valuable minutes.
De Bruyne is the big one, though. City's talisman is still the player that invokes the most fear when opposition players step onto the pitch, and respect when they name the best players in a calendar year. Against Leeds, he looked exactly like the man that has tormented so many Premier League sides before in his seven years at the Etihad.
If De Bruyne is back to even close to his best, a very sticky December will suddenly look a whole lot easier.
