The hosts came into the fixture on a good run of form, having gone nine games unbeaten in all competitions but Guardiola had a very good recor1d at Old Trafford and had not lost a league match at the Theater of Dreams since arriving in England.
He fielded an unfamiliar backline, while injury also ruled out star man Kevin De Bruyne but even in his absence, Manchester City dominated the early proceedings, with the hosts forced to sit back and absorb the pressure.
Manchester United, however, had the best chances of the early periods and went ahead through Anthony Martial from a well-worked freekick in the 30th minute.
Smart tactical decisions by Ole Gunnar Solskjaer guaranteed that his side saw out the match and Scott McTominay struck the decisive blow late into injury time to ensure that the Norwegian became only the second manager after Nuno Espirito to win Guardiola home and away in the same league campaign and equalled Jurgen Klopp's record of defeating the Catalan three times in a single season.
The win gave Manchester United an invaluable three points in their quest for a top four finish and here, we shall be highlighting five players who shone for the Red Devils in their derby day delight.
5. Harry Maguire
Manchester United have kept four consecutive clean sheets at Old Trafford and seven in their last nine games in all competitions and a large reason for their improved defensive solidity has been the performance of their skipper.
The former Leicester man was once more a defensive rock at the back and led by example with his tireless contributions and marshalling of the defence in the face of sustained pressure by the City attackers.
Bar a mistimed header in the first half, Maguire did not put another foot wrong all match and was up to the task of keeping Sergio Aguero quiet.
The 27-year-old made six clearances and two interceptions, limiting City to just one shot in the first half (their lowest since October 2018) and he continued his job of slowly winning over critics who scoffed at the word record fee paid for him in the summer.