Frank Lampard insists it is too early to make a judgement call on whether Chelsea will be able to challenge Liverpool for the Premier League title this season.

Chelsea have spent close to £200million on bolstering their squad heading into this season, yet they were comfortably second best against the defending champions on Sunday.

With Andreas Christensen seeing red late in the first half, Sadio Mane's quickfire double – his second coming courtesy of a Kepa Arrizabalaga error – secured the points in a 2-0 win for Liverpool.

Timo Werner won a penalty after a collision with Liverpool debutant Thiago Alcantara, only for Jorginho to fail from 12 yards to round off a frustrating game for the Blues at Stamford Bridge.

However, Lampard does not believe the result means his side cannot challenge for the title this season.

"I expect us to be competitive with Liverpool. We competed in every game with them last year," Lampard told a news conference.

"With the Kepa situation it's a clear mistake. A clear mistake that has cost us because at that point we go on to have a penalty which we maybe score. Those fine margins change games at this level. 

"I don't think you can ever make judgements on a game that's tight for half a game and then becomes 10 against 11 and the game completely changes.

"I was really pleased with the spirit and work ethic and some of the individual performances. There's a lot for us to look forward to.

"We have players coming in, players coming back who are injured, some of them are new signings. We will get more time and days to work together to get fitness but also in the way we want to play.

"There were flashes of it today. We'll see a lot more of that. It's not the time for judgements. It's game two, we had 10 men against Liverpool. We almost can come away with a 1-1 if circumstances change and I think there were a lot of positives."

Rennes goalkeeper Edouard Mendy seems set to come in and add competition in that position, though centre-back Antonio Rudiger was left out of Chelsea's squad on Sunday.

"We have five centre-backs at the club and I can't pick a squad that has three of them on the bench," explained Lampard, who went with Fikayo Tomori, a reported Everton target.

"That is the way it is, I have to pick a squad via training and situations and that was the selection today."

At the other end of the pitch, striker Werner was limited in terms of opportunities, but Lampard has been impressed by the former RB Leipzig star.

"I'm very pleased with his start. We brought him to the club for the attributes we are seeing," he said. "We will see goals from him.

"Today he comes up with a moment that could get us back into the game. I'm delighted with him, we'll see a lot more, and also his manner, his way, his desire to work for the team."