The forward came off the bench at the break with the score locked at 1-1 to inspire the visitors to a 3-1 win on Sunday.

His first Premier League goal since September's brace against Villa put Chelsea ahead and he then won an added-time penalty for Jorginho to score.

It was the Italian's second from the spot after he cancelled out Reece James' own goal in the first half.

Lukaku has been blighted by an ankle injury and then COVID-19 since October and while Tuchel was delighted with his impact, he said it was "not fair" to force him back into action for a full half.

"There is no doubt he is super-important. Romelu will be a key player," Tuchel said.

"I am very impressed with my players but super-concerned.

"Maybe we made a big mistake here letting players play after corona and one or two training sessions. But obviously they (the Premier League) made us play and so we play.

"This cannot be the right way. People at the green table and people in offices take these decisions. This is how it is."

Villa were without boss Steven Gerrard, who is isolating after testing positive for COVID, with assistant Gary McAllister leading the squad.

"I've been speaking to Steven ever since he was diagnosed. He is obviously very frustrated, it's a game he wanted to be part of," McAllister said.

"He is due to be back on Friday and we have four or five days to work and try to correct the things which didn't go so well and look to build on what we've done.

"Even though I thought we played some good football, to get an end product I thought we lacked a bit of imagination. There has to be an outcome after your good play."

Australian Associated Press