Marcus Rashford has told Manchester United fans he tried to carry on injured against Wolves - because he didn't want to let them down.
Rashford appeared to suffer a back problem in an innocuous-looking challenge with Matt Doherty after coming on as a second-half substitute.
He received treatment and came back on to the pitch, but was struggling to run and ended up on the turf once again before limping down the tunnel.
The striker took to Twitter after the game, posting: "Never want to feel like I’ve let my teammates, the club and most importantly the fans down so did my very best to carry on tonight and was gutted to come off.
"Top work from the lads to get into the next round."
Rashford started on the bench and United boss Ole Gunnar Solskjaer would have hoped he would not need to call on his top scorer.
But with the game scoreless midway through the second half, he turned to Rashford. And Juan Mata made the breakthrough just minutes later.
Rashford suffered the injury shortly afterwards, and Solskjaer admits he doesn't know whether his talisman will be fit for Sunday's trip to runaway Premier League leaders Liverpool .
"That backfired but you have got to go for them once in a while," Solskjaer said of his decision to bring Rashford on to BT Sport. "It seems like he has got a knock there and he couldn't run.
"We will test it in the next few days and we will see. Hopefully he will be OK for Sunday but I don't know.
"He has struggled with a couple of knocks with his back lately. He got another one and it didn't help."
