Chelsea coach Ray Wilkins hailed Nicolas Anelka as "outstanding" after the holders secured a place in the fifth round of the FA Cup.
Anelka made the breakthrough in the 36th minute against Coca-Cola Championship side Preston at Deepdale with his 11th goal of the season. Daniel Sturridge then sealed a 2-0 victory with a goal two minutes after half-time.
Wilkins said: "From our perspective Nicolas is playing some outstanding football. He is a joy to have around the place."
He added: "He enjoys his training, he is working extremely hard and he is getting the rewards from that."
Anelka's goal came when he brushed past Youl Mawene and fired in a shot that had too much power for impressive goalkeeper Andy Lonergan.
Preston should have equalised but Darren Carter somehow steered the rebound wide after Hilario had palmed away a header from Chris Brown.
It proved to be the turning point as Sturridge added a second two minutes in the second half after John Terry's header rebounded to him.
It was Sturridge's third goal since he arrived from Manchester City in the summer and Wilkins said: "We are pleased with Danny.
"He has a lot of talent and is working extremely hard. For young players at Chelsea it is really difficult to get past the likes of Nicolas and Didier (Drogba). But he is looking a good player."
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