After a long spell of treatment, Antony attempted to walk off the pitch but winced at the pain as he put pressure on his ankle - leading to him being carried out of the game with his hands over his face.
It meant an earlier-than-planned opportunity for Marcus Rashford to enter the fray, after being benched on his return from illness.
But United were already in the lead thanks to Casemiro’s second goal in as many games, the Brazilian powering a header home from Christian Eriksen’s sixth-minute free-kick.
Chelsea were guilty of several bad misses in a first half they largely had the better of, Mykhailo Mudryk failing to convert a fine Lewis Hall cross before the goal with Conor Gallagher and Kai Havertz also guilty in front of goal.
They were made to pay in the long first-half stoppage time when Casemiro’s delicate dink into the box was squared by Jadon Sancho for an Anthony Martial tap-in.
United came out to try and kill the game, Bruno Fernandes hitting the crossbar early on before Kepa Arrizabalaga clawed a difficult Christian Eriksen attempt off the line.
Casemiro ➡️ Sancho ➡️ Martial! 🔥
The goal to seal Champions League qualification for Manchester United? pic.twitter.com/kJ1fHiet8G
— Sky Sports Premier League (@SkySportsPL) May 25, 2023
Chelsea’s resolve was soon crushed with Wesley Fofana nutmegged by Fernandes before lazily tripping him in the box, allowing the Portuguese midfielder to net the third from the spot.
Rashford added a fourth with 12 minutes left after another Fofana error, ensuring their top-four finish with the advantage over Newcastle for third place going into the final day despite Joao Felix’s consolation.
Man United host Fulham before the FA Cup final six days later, which will require a speedy recovery from Antony, while Chelsea welcome the Toon to west London.