"I think Tomori played very well for me last year and is training at a very high level, Lampard said.

"There is competition at centre-back, he deserved to play and I thought he played well. It was just a choice."

Chelsea have conceded nine goals in their opening four games, including four to teams promoted from the Championship, which leaves Lampard looking for defensive solutions.

He will be helped by the return of Antonio Rudiger after the international break and the former Derby manager is not worried about the make-up of his back line.

"No, I wouldn't say I was worried about it," he said. "I am trying to work all over the team to get the right combinations.

"Rudiger is fit after the international break which gives me another choice.

"We can isolate goals and talk about centre-backs or whatever – it's not (just down to them), it's the team.

"When we score goals, sometimes it's because of the centre-back playing the ball quickly.

"I am not relating to the centre-back issue. I trust the four centre-backs I have completely, we are just in a moment where obviously we need to stop conceding goals."

The Blades looked dead and buried at half-time after trailing to Tammy Abraham's double but they mounted a recovery in the second half and earned a point thanks to Callum Robinson's strike and a Kurt Zouma own goal.

Left-back Enda Stevens said his side showed Chelsea too much respect in the first half and wants them to use the result to build belief.

"The finish was brilliant, it's what we need to do, but we need to start games like that," he said.

"I know we are playing at Stamford Bridge and playing against great players but the occasion can't get the better of us.

"We have got to control our emotions and be smarter. We did that in the second half and we go into the international break on a positive.

"We have got points on the board and we are building to where we want to be and hopefully – after the break – we can really kick on."