It was a remarkable encounter between two clubs having a season filled with ups and downs. However, it was Chelsea who took an early lead through Connor Gallagher before Cole Palmer doubled their lead from the penalty spot.
Then chaos occured, Caicedo with a lapse of judgement gifted Garnacho, to give Manchester United a lifeline back into the game.
Captain Bruno Fernandes does what he does best by providing his team a quick equaliser after he headed home a brilliant cross from Diogo Dalot.
In the second half, Antony whipped in a delightful outside of the foot cross right on the head of Garnacho to get his brace to turn the game around for Manchester United.
Manchester United thought they were leaving London with all three points in their quest for Champions League football. However, substitute Noni Madueke was clipped by Diogo Dalot late into injury time, to give Chelsea their second penalty of the game.
Cole Palmer stepped up and converted which what seemed to be a priceless draw for his side.
Astonishedly, a minute later Cole Palmer got himself the matchball by scoring his hattrick and winning the game for Chelsea in remarkable fashion.
Palmer now has 16 goals in the Premier League with eight of them coming from the penalty spot.
In addition, only Yaya Toure and Dimitar Berbatov have taken more penalties while converting 100% of them than Cole Palmer who has 8 from 8.
This now leaves Manchester United 11 points off Aston Villa and 9 points off Spurs.
It was also the latest winner scored in Premier League history, timed at 100 minutes and 39 seconds.
Manchester United have now lost 12 Premier League this season, the most they have ever had in a single campaign.
Erik ten Hag blamed individual errors and poor decision making the defeat against Chelsea
Here's what he had to say.
"We made individual errors that cost us the game. We have to learn from it. When you're a Man Utd player you should already know how to deal with this circumstance. In five days we dropped five points. That is unacceptable."
Palmer was jubiliant and shocked after his hattrick. He went onto say:
"It was madness. To win like that, there is nothing better. We thought when we scored the third goal the fans lifted us and I saw the gaffer say there were two minutes left and thankfully I scored."
Mauricio Pochettino was over the moon with his side's victory. He said:
"Of course I enjoyed it. It was amazing because I was thinking we deserved it, we were the better team today. It was fair when we scored in the last minute.
"We started the game really well and at 2-0 for us the game was under control. Then we made a mistake and we suffered a big emotional impact. It wasn't easy to deal with this."
The Argentine also explained why it was so important they won the game. He said:
"It was very emotional at the end because of the way it happened and it felt really unfair when we were losing. The feeling was not so good because we were thinking why we were losing the game"
"For us it was really important because it was a must- win game if we wanted to reduce the gap to the teams above us. The three points today was so important"
Chelsea still chasing down a European place and still have a game in hand on those around them and now only 5 points behind Manchester United.
Both teams still have an FA Cup semi final to play. Chelsea play Manchester City and Coventry play Manchester United.
Man of the Match- Cole Palmer
It has to be really. City's boy and Chelsea's man having an exceptional first season for Chelsea and fulfilled that by getting himself the matchball.