Romelu Lukaku lived up to his self-styled "sergeant" tag with an emergency stint at centre-back during Manchester United's 3-2 win at Crystal Palace.

Belgium striker Lukaku netted the equaliser at Selhurst Park on Monday before Nemanja Matic's stunning long-range strike sealed a remarkable comeback from 2-0 down in stoppage time.

Jose Mourinho had already used his three substitutions by that stage and responded by asking Lukaku – who described himself as the United boss' "sergeant on the field" this week – to drop in as an extra central defender.

"He is an important guy for me," Mourinho told reporters ahead of Saturday's crunch Premier League clash against rivals Liverpool at Old Trafford.

"He is one of the guys that I trust. I love the attitude, I love the character. Against Crystal Palace there was nothing that happened after our third goal.

"I told him 'central defender' and after the third goal he was playing in a back five with [Chris] Smalling and [Victor] Lindelof because I couldn't make any more changes.

"When I say to the striker, 'go there and do the job for me' he is a sergeant. He is someone you can trust. His attitude is phenomenal.

"It's not just about the goals he scores; it is about when he brings to the team. That spirit."

Eric Bailly, a far more conventional central defender, is back to full fitness for United this weekend, while Marouane Fellani is set to return after his latest spell on the sidelines with a knee injury.