Mendy made his first Chelsea appearance after leaving Rennes in a reported £20million deal last week and impressed, despite Tuesday’s 5-4 penalty shoot-out defeat in the round of 16.
Starting ahead of embattled team-mate and the world’s most expensive goalkeeper Kepa, who was dropped for the 3-3 Premier League draw at West Brom as Lampard turned to Willy Caballero, Mendy produced a good save to thwart Sergio Reguilon in the second half.
Discussing Mendy’s performance at Tottenham Hotspur Stadium, Lampard told reporters: “I thought he was very good. I think he made a couple of good saves, one particularly good save.
“He came and caught a few balls, even the one he comes for and doesn’t catch, the idea that he wants to and be positive isn’t a bad thing. Very, very pleased with every part of his game really.”
Werner – a high-profile signing from Bundesliga side RB Leipzig – struck his first Blues goal 19 minutes into the contest before Tottenham’s Lamela drilled past Mendy with seven minutes remaining.
The first nine penalties of the ensuing shoot-out were converted before Mason Mount clipped the outside of the left post with the 10th, allowing Spurs to progress.
“Listen, I don’t think ‘a shattering blow’ is what it should be, I know it was a disappointing night to get knocked out of the Carabao Cup,” Lampard said. “Mason will have many more nights for this club and for his country where he’ll play in games of huge importance and he’ll be the deciding factor in a positive way.
“So no, Mason’s got my support at all times, and the team’s, and everybody around it. You miss a penalty, it’s a collective when you get this far in a game like this.”
Lampard added: “We were dominant and you want to score more goals at that point because of the amount of possession and chances. Callum [Hudson-Odoi] had a good chance for us in the first half.
“I think probably Tottenham would have felt that, they would have felt that hard and they changed their game and went longer in their build, which meant our press, which had been fantastic in the first half, wasn’t so relevant up the pitch. They turned us round and made us run backwards rather than being able to press forwards. And then it becomes really difficult, to be fair to the lads.
“We could have been better in the second half and maybe dealt a bit better with that physical nature of Tottenham’s game but it slightly changed the case of the game but I think even so, they had some chances second half and so did we and at 1-0, one more goal finishes it for us and we didn’t get that.”