TAMMY ABRAHAM gave Frank Lampard some much-needed relief with an FA Cup hat-trick against Luton.
Chelsea made it through to the fifth round where they will face Barnsley after a 3-1 win at a snowy Stamford Bridge.
But the world's most expensive keeper Kepa flopped again with a clanger gifting Nathan Jones' men a way back into the game at 2-1.
And reserve left-back Emerson Palmieri also struggled, while Timo Werner's confidence took another dent as he missed a penalty late on.
SunSport dishes out ratings for all the Blues stars.
Kepa Arrizabalaga - 5
Should have saved Luton's goal despite having his vision slightly impaired. He should be stopping those and it was another clanger from the Spanish keeper.
He did a bit to redeem himself in the second half with one big and important save at 2-1 up, and another one not long after.
Reece James - 8
Looked back to his energetic and emphatic self after a few quieter games.
Delivered some fine crosses and was involved in all of Chelsea's good build-up play.
Kurt Zouma - 5
Struggled after seemingly picking up a knock, and he should have done better to block the shot for Luton's goal.
Andreas Christensen - 6
Looked more assured than his fellow centre-back, and didn't have a great deal to do other than for the goal.
Emerson Palmieri - 4
Poor from him, never looks to advance with the ball enough, and was sluggish at the back not closing down quick enough or filling the spaces.
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Billy Gilmour - 8
Cool, calm, and collective - the best three words to describe Gilmour.
He was quick and progressive on the ball, and always puts the perfect weight on his passes. He was involved heavily in Abraham's well-worked third goal.
Mason Mount - 8
Captain Mount lead by example once again. He was quick on and off the ball, used it well, threatened in attack and was quick in both transitions.
Hakim Ziyech - 7
Fairly quiet in the first half and didn't really do a lot to get himself involved enough, but the second half he switched on he was a different class being behind a lot of Chelsea's threatening attacking play.
Christian Pulisic - 4
Should have scored two in the first half, especially the one on one with the goalkeeper, and he also missed a very good chance in the second half. He's looked like a player without confidence recently, but can at least still say he is putting in the effort. Very poor game from him.
Timo Werner - 6
Much more comfortable and confident performance from him playing in his preferred central position closer to another striker.
He wasn't as good dropping in, but when close to Abraham playing off him, he looked class. Second-half he dropped off though and his form was summed up with a late penalty miss.
Tammy Abraham - 9
Great display from Abraham, two good finishes in the first half and he was a lot like Mount in leading by example, chasing lost causes, and putting in maximum effort for the team.
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He capped off a man of the match performance by getting his hat-trick in the second half.
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Callum Hudson-Odoi (for Pulisic, 70) - 9
Instant impact from him, made things happen and set up Abraham for his hat-trick.