Manchester moved to within six points of the Premier League summit with a 2-1 comeback victory over Manchester City at Old Trafford.
Pep Guardiola’s City struggled to carve out openings in a tense opening period and it was the hosts who had the better opportunities.
Bruno Fernandes sizzled just wide of the far post from a narrow angle before Rashford had a shot blocked on the line and an effort well saved by Ederson.
City stepped up a gear following the interval and Grealish broke the deadlock within 193 seconds of emerging from the bench when he headed home Kevin De Bruyne’s cross on the hour mark.
However, United stunned the away side with two goals in four minutes to turn the game on its head.
First Rashford left a through pass from his offside position, allowing Fernandes to arrive from deep and fire home the equaliser on 78 minutes.
Rashford was then perfectly placed to tuck in from close range eight minutes from time after a lovely turn and cross from substitute Alejandro Garnacho.
The result means United move up to third spot, just one point behind Man City and six adrift of leaders Arsenal, who face Tottenham in the North London derby on Sunday.
Next up, Man United visit Crystal Palace on Wednesday while Man City host Tottenham on Thursday night.