Marcelo Bielsa's side claimed an impressive three points against the Premier League's champions-elect.
The Whites went ahead through Stuart Dallas in the first half but were up against it following a red card for captain Liam Cooper after VAR intervened over a tackle on Gabriel Jesus.
Leeds defended deep in the second period and were finally undone through Ferran Torres as the wide man struck 14 minutes from time.
City again pushed on but it was the 10 men of United who burst through in stoppage time as Dallas slid home an unlikely winner to spark wild celebrations across the Pennines.
Here, we take a look back at the best pictures from a memorable afternoon for Leeds United in Manchester:
1. Pre-match respects
There was a two minute silence ahead of the game following the passing of Prince Philip on Friday. Photo: Getty
2. Cooper blocks
Liam Cooper provides a crucial block in the opening exchanges as Ferran Torres looks to open the scoring with a volley from a corner. Photo: Getty
3. Pep v Bielsa
Marcelo Bielsa and Pep Guardiola watch on at the Etihad as two good friends meet in opposition Premier League dugouts for a second time. Photo: Getty
4. Dallas scores
After some good play from Helder Costa with Leeds playing on the break... Patrick Bamford lays the ball to Stuart Dallas who drills a low shot off the inside of the post. Photo: Getty
5. Leeds celebrate
An unlikely lead but Dallas' goal gives Marcelo Bielsa's team the opener as they keep City at bay in the first half. Photo: Getty
6. Cooper red
Disaster strikes in first half stoppage time. Cooper's tackle on Gabriel Jesus is upgraded from a yellow card to a red after a VAR review.