Erik ten Hag fears winger Antony suffered a "serious" injury as Manchester United fulfilled the "main objective" of Champions League qualification by thrashing Chelsea.

The Red Devils sealed their return to European football's top table with a game to spare by thrashing Frank Lampard's wasteful Blues 4-1 at Old Trafford on Thursday evening.

Casemiro, Anthony Martial, Bruno Fernandes and Marcus Rashford scored before Joao Felix struck a late consolation on a night that saw Antony leave on a stretcher in the first half.

Asked for an update on the Brazil international, Ten Hag said: "I don't know. Everyone has seen he came off.

"I can tell you that it's serious but we have to wait minimum 24 hours and then we know probably more about the status of his injury."

Ten Hag's comments suggest Antony is in danger of missing the FA Cup final against Manchester City on June 3, with Luke Shaw also requiring assessment after being substituted with a reported back issue.

"We have to wait," he said. "Antony looks serious but we don't know what it is. With Shaw, we have to wait as well. After tomorrow we know more."

Their absence would be big blows for a United side that are already without Lisandro Martinez, Marcel Sabitzer and Donny van de Beek for the FA Cup final.

Beating City would be the cherry on top of what Ten Hag believes has already been a "successful season".

"I have always high expectations of myself and I think this club belongs in the Champions League, so you have to qualify in the first four," he said.

"But this league is very strong, and there are many teams, many clubs, who are competing for the position and they all can do it because they have high budgets, good squads.

"We see Chelsea, they have massive, good squad with outstanding players.

"So, we are happy we are in the first four. I think we played a good season in the Premier League. I would say, a very good season."

Put to Ten Hag that former Arsenal boss Arsene Wenger said finishing in the top four was the equivalent of winning a trophy, Ten Hag said: "Oh, I think in the Premier League, yeah, it's something like that.

"That is, I think, the main objective of the season, to get in the Champions League.

"So, therefore you have to see yourself in the top four and, as I just tried to respond, the competition is tough.

"It's many teams with really good squads, good managers, so when you are in there you're doing a good job and your team is playing well and performing well.

"I think this is for this moment the maximum, but we want more."

That hunger for more means backing is required in the summer transfer window, whoever United's owners are.

"You have to see how you come out of the transfer window," Ten Hag added.

"But if I see now I think we need more, so I don't have so much patience. And that is one of my mistakes."

Chelsea were already guaranteed to finish in bottom half for the first time in 27 years before this club record 16th defeat in a 38-game Premier League season.

Interim boss Frank Lampard was understandably downtrodden in the press conference that followed his eighth loss in 10 matches in charge.

"My personal feeling? I don't think it's about my personal feeling, I think it's probably about the reality of where we're at," he said.

"I've said it a lot going into the game, when things are off for a period, which has been the season for us – you can trace it back to probably pre-season – and then it's not easy to turn it.

"Then when you get into a run-in against top clubs that are going for something, nothing's a given in this game.

"Mixed feelings. We played OK in parts today, there was some individual performances within the game, which I think can be nice shoots for the future if they're worked on.

"But of course the reality is when you come to Manchester United and how clinical they are in front of goal and how non-clinical we were, how we defended individually poorly in the second half, then the result can come."

Manchester United boss Erik ten Hag provides Antony update as fears grow over 'serious' injury