Frank Lampard has come to the defence of Chelsea pair Kepa Arrizabalaga and Timo Werner after they progressed into the fifth round of the FA Cup.
But the Blues could've had not only a clean sheet, but more goals too.
Luton's goal came cross Jordan Clark who fired past Kepa in the first-half, but it was a mistake by the Spaniard who should have kept it out.
However, Lampard was quick to defend Kepa after he kept Chelsea in the lead thanks to an excellent save to deny Harry Cornick in the second-half.
"Well, on the flipside of that, Kepa makes a really top save in the second half to make sure it doesn't go to 2-2. It is very easy for people to sort of hone in on that but Kepa is not playing so regularly," Lampard said, as quoted by Goal.
"He comes in after training well and he is a good goalkeeper and I will certainly give him that one in the first half.
"I am as annoyed that we let someone stand in our box in space and get a shot away when we shouldn't have done. I think it was a general team moment of complacency with how we were at 2-0 which is not good enough.
"So, we got back to it very quickly and dominated the game and it made us slightly nervous to not have the two goal league that makes it comfortable. Once we got that back again, which we should have got a lot earlier, then the game was comfortable."
Werner then had a chance to make it 4-1 late on from the penalty spot but Simon Sluga denied the German, to block him from scoring in both the third and fourth round.
"With Timo I’m disappointed for him," added Lampard. "He gave a lot to the performance today. He was a threat behind, his link up with Tammy, his link up with people around him, it’s just one of those things," he said.
"When it’s not going for you quite, it can happen. I missed penalties, I know the feeling. I know he will feel despondent, maybe now and the last few minutes of the game, but he shouldn’t be.
"It’s my job and his teammates’ job to lift him and he will be fine. It was almost a sign of what’s going on for Timo at the minute, it’s not quite dropping for him, but there will be a time when he takes penalties without thinking about it and hits the back of the net without thinking about it. At the moment that’s not quite the time for Timo, but it will come and hopefully soon."