This one-nil defeat to West Bromwich Albion was a miserable performance in its own right, made all the more galling by the fact that as a result, Manchester City have been confirmed as Premier League champions.
In a match that can keep United within a mathematical chance of finishing top of the Premier League - although nearly impossible - a defeat against West Brom would mean City finally clinch the Premier League trophy with five games spare.
City nearly secured their status as champions last weekend, as they went into half-time against United with a two goal lead.
Guardiola has won titles with Barcelona and Bayern Munich, while also conquering the Champions League during his Camp Nou reign. "You can not say that Manchester City won the title because Manchester United lost a game". However, after Tony Pulis's departure, under new boss Darren Moore, West Bromwich started with a draw against Swansea and they will be aiming for an upset against United. With City able to clinch the league title in front of their rivals, they began the match in electrifying fashion.
United manager Jose Mourinho will likely be content with the options at his disposal, with only a selection of fringe players in doubt for Sunday's game.
After going two goals down, United sprang to life in the second half to scored thrice to deny City from winning the title on the night. Whatever happened with United, City have five games to secure the points needed for the title.
He said: "We've got faith in one another, the players, the staff. Things have gone a bit by the wayside this year".
Ander Herrera 5 - His role against Manchester City was clear and well executed, but it was completely in the opposite here. They won the title because they were the best team, because they won a great amount of points.
It was always a matter of when rather than if City would be champions after they led the way for most of the season.
While it may be premature to place City in that rarified air, they could make a case by breaking the Premier League points record of 95 set by Chelsea in 2004-05.
Among countless star turns in Guardiola's side, Kevin De Bruyne has been the standout.