Anthony Martial and Harry Maguire scored either side of the interval as United completed the double over Chelsea for the first time in 32 years. Chelsea were left frustrated after having two goals ruled out by VAR, first a Kurt Zouma header after a push on Brandon Williams and then an Olivier Giroud strike for offside.
Frank Lampard's side were ultimately second best and saw the gap between themselves and seventh-placed United reduced to just three points as the chasing pack close in on fourth spot.
Here are the three things we learned as Manchester United beat Chelsea 2-0 at Stamford Bridge.
3. VAR strikes again
Chelsea's bench were left furious after Harry Maguire tangled with Michy Batshuayi on their touchline in the first half. A clear kick-out on Batshuayi, akin to Son’s red card against Chelsea earlier in the season was controversially not deemed as violent conduct by referee Anthony Taylor, and VAR official Chris Kavanagh deemed there was no need to rectify what was not deemed a clear and obvious error.
VAR wasn't done, yet. Towards the start of the second half, Fred pushed Cesar Azpilicueta, who fell into Brandon Williams, who then went down inside the area. As the ball flew over the young defender’s head, Kurt Zouma was there to net an equaliser only for the men in Stockley Park to decide it was the Chelsea captain who had committed the foul.
Giroud's goal was rightly ruled offside, but on another day and with a different set of eyes casting their verdict, United might not have been so lucky with the first two decisions.
2. Wasteful Chelsea pay the price
The reverse fixture between these two on the opening day of the season was perhaps the most egregious example of ‘result doesn’t reflect the game’ you’ll ever see. United won that 4-0 at Old Trafford but Chelsea were the better team throughout and paid for their high defensive line, passive midfield and an inability to take their chances. Six months on, and Chelsea seemed to have learned nothing since then.
Once again they dominated possession and had plenty of chances, but for a second time this season they failed to capitalise and were hit on the counter-attack. A host of opportunities were spurned by the Blues and Michy Batshuayi, in particular, looked like he had left his scoring boots at home.
Anthony Martial and Aaron Wan-Bissaka were on point last evening as the latter delivered a pinpoint cross, which was perfectly nodded in by Martial with a textbook No.9 finish.
1. Top four race blows wide open
Chelsea have long been camped in the Champions League places as a result of their strong start to the season. United, on the other hand, have been playing catch-up from the outset. But last evening's victory leaves Ole Gunnar Solskjaer’s side just three points away from Chelsea in seventh.
With Manchester City facing a ban from European competitions in 2020/21 - fifth position in the Premier League table would be high enough to earn a Champions League spot next season.
Eleventh-placed Burnley are only 7 points off Chelsea and the congestion in this area of the table means the race for Europe will go down right to the wire – with Chelsea, Spurs, Everton, Arsenal, United, Burnley, Wolves, and Sheffield United all in the mix.
Last evening's game, however, could have serious ramifications for two sides expecting to play Champions League football next season.