Juan Mata's controversial second-half penalty was enough to earn Chelsea their place in the fifth round of the FA Cup with a 1-0 win over Queens Park Rangers at Loftus Road.
The 24-year-old Spaniard calmly slotted home from 12-yards after Clint Hill was adjudged to have fouled Daniel Sturridge on the edge of the six yard box as he attempted to latch on to Mata's perfectly weighted cross.
The pre-match talk surrounding John Terry and Anton Ferdinand, whose paths crossed for the first time since the west London rivals' Barclays Premier League clash back in October, meant for an electric atmosphere.
As the players emerged from the tunnel the Chelsea captain was met with a chorus of boos, while Ferdinand received a heroes reception. But despite the fiery atmosphere off the pitch, on it both side's played out an energy-bereft first half with very little chances created.
Mata created Chelsea's only real chance, forcing a low save from Rangers keeper Paddy Kenny, after seizing on a slip from Luke Young.
Meanwhile, Joey Barton had QPR's best effort, striking a 20-yard half volley which was watched comfortably by Petr Cech, as it fell wide of his far post.
Chelsea started brightly after the break, with Sturridge going close after some neat play by Fernando Torres.
The visitors were unlucky not to be awarded a penalty when Hill brought down the lively Sturridge, but referee Mike Dean awarded a corner rather than a spot kick.
However, moments later the same two players tangled, and this time Dean was in no doubt about pointing to the spot, despite it looking a very soft penalty on second look.
With 15 minutes to go Ramires suffered an unfortunate injury after blocking a shot that led to a lengthy delay and seven minutes added on time.
The Brazilian was stretchered off, and in the closing stages QPR came to life, with Young first, and then Shaun Wright-Phillips drawing saves from the Chelsea goalkeeper.