Enzo Maresca made wholesale changes to his side, naming a completely different XI from the team that beat Everton at the weekend.
The hosts, who sit top of League One with 41 points and a four-point cushion at the summit, played with energy and belief and proved difficult to break down in the opening period.
With the contest finely balanced, Maresca turned to his bench at half-time, introducing Alejandro Garnacho and Joao Pedro. The changes immediately shifted the momentum, with Chelsea applying sustained pressure on a Cardiff defence that had previously held firm.
Garnacho broke the deadlock in the 57th minute after Dylan Lawlor was caught in possession, allowing the winger to capitalise.
Cardiff briefly reignited hopes of an upset when David Turnbull headed an equaliser with 15 minutes remaining, his first goal in 13 months and a moment that lifted the last remaining EFL side in the competition.
However, Chelsea’s quality told once more as Pedro Neto restored the lead with a strike described as a moment of clear Premier League class.
Garnacho sealed the win in stoppage time with his second goal of the night. Moises Caicedo also returned after a three-match domestic ban, as Chelsea’s bench proved decisive.
“I’m very happy, especially for the effort of the players. I said yesterday that football is full of these tricky games so you have to pay attention and we did a good game,” Maresca told Sky Sports.
“Off the ball, we were quite good, on the ball, we struggled a bit to create chances [in the first half] for many reasons. Second half we were much better on the ball.
“It was a big difference between the first half and second half, the way we attacked also. Cardiff were very organised and intense. In the end, we did enough to win the game.”
