Manchester United have thrown open the race for the final Champions League qualification spot in the Premier League by beating fourth-placed Chelsea 2-0.
Headed goals from Anthony Martial and Harry Maguire either side of halftime helped United complete the league double over the 'Blues' for the first time since the 1987-88 campaign.
The visitors to Stamford Bridge were aided by video assistant referee (VAR) decisions that denied the hosts two goals, while Maguire avoided being sent off for a kick on Michy Batshuayi.
Seventh-placed United are now just two points behind fifth-placed Tottenham Hotspur and three behind Chelsea themselves.
But VAR and its interpretations dominated the discussion afterwards.
"Harry Maguire should have been sent off, that's clear, and that obviously changes the game," Chelsea manager Frank Lampard said.
"[Cesar] Azpilicueta gets shoved, so the goal [by Kurt Zouma] should stand.
"[Olivier] Giroud was a toenail offside and that one I understand, that's the rule now.
"I don't get why they aren't looking at the monitor. It should be used."
Maguire escaped a booking, after he appeared to kick out at Batshuayi, an incident that could have seen him sent off.
"I know I caught him and I felt he was going to fall on me, and my natural reaction was to straighten my leg to stop him," United captain Maguire said.
"It wasn't a kick-out and there was no intent. I think it's the right decision."
Martial scored a fine opening goal, flicking a header into the corner from a superb cross from Aaron Wan-Bissaka.
Chelsea thought they had levelled the scores on 56 minutes, when Zouma headed home from a corner.
But his effort was ruled out by VAR for a push by Azpilicueta on Brandon Williams, even though replays showed Fred had pushed the Chelsea defender first.
Maguire thundered in a header for United's second from a Bruno Fernandes corner 10 minutes later.
Chelsea were denied a goal by VAR for a second time, when Giroud was adjudged marginally offside before he netted.
Odion Ighalo came off the bench to make his United debut and almost scored a third late.
Lampard said he felt his side was hard done by.
"Tough to take on lots of levels, some footballing, some others," he said.
United boss Solskjaer said the result gave his side's Champions League hopes a boost.
"That's four [clean sheets] on the bounce now, we're getting better defensively," he told Sky Sports.
"It gives us confidence. It gives us a chance, it's going to be a tight race [for a top-four place]."