Chelsea moved 12 points clear at the top of the Premiership after grinding out victory over 10-man Everton.
On only eight minutes, James Beattie was sent off after head-butting William Gallas in an off-the-ball incident.
Eidur Gudjohnsen tapped home the winner in the second half after Gallas had hit the bar.
Despite their advantage, Chelsea struggled for long spells with a stubborn Everton side and an awful Goodison Park playing surface.
Both sides were affected by the trampoline of a pitch, which hardly assisted attempts to move the ball around.
Chelsea coach Jose Mourinho had already expressed his concern before the game, saying he expected a fight rather than a good game of football.
He couldn't have realised Beattie would take it literally.
Beattie wasted little time in leaving his mark on the Chelsea defence.
It was hard to know what was going through his mind - aside from the back of Gallas' head - as he pursued the Frenchman down the touchline.
With the ball well out of reach and rolling harmlessly beyond the goal line, Beattie seemed determined to make contact with something.
And he head-butted Gallas, not once but twice.
Referee Mike Riley immediately - and appropriately given Beattie's bull-like behaviour - flashed red at the Everton man.
Chelsea, though, found their opponents just as difficult to break down as they would have been with a full complement of players.
The closest they came to a first-half goal was when Damien Duff's cross was deflected goalwards by a combination of Gudjohnsen and Alan Stubbs.
Martyn's knee kept the ball out on that occasion.
The in-form keeper later made more orthodox stops from shots by Frank Lampard and Tiago to keep Chelsea out.
At the other end Petr Cech hardly had a save to make to extend his Premiership record to 10 consecutive clean sheets.
He got down well to smother a second-half Lee Carsley header but, inevitably, Everton attacks were rare.
Not that Chelsea were that much more potent going forward.
Martyn made a superb stop from Gudjohnsen mid-way through the second half after the striker latched on to Duff's shot.
But otherwise, Chelsea's shots from distance did not prove too much of a threat.
It took the impressive Gallas to help create Chelsea's winner, when he directed a cross from the right on to the bar.
The predatory Gudjohnsen was fastest to react to slot the ball into an empty net.
It was enough to earn Chelsea three points as they continued their march towards the title and harmed Everton's push for Europe in the process.
Everton: Martyn, Pistone, Weir, Stubbs, Naysmith (Ferguson 73), Yobo, Bent, Carsley (Arteta 85), Cahill, Kilbane, Beattie.
Subs Not Used: Wright, Plessis, Gerrard.
Sent Off: Beattie (8).
Chelsea: Cech, Paulo Ferreira, Gallas, Terry, Bridge, Cole (Jarosik 72), Tiago (Johnson 90), Makelele, Lampard, Duff (Ricardo Carvalho 90), Gudjohnsen.
Subs Not Used: Cudicini, Smertin.
Booked: Terry, Jarosik.
Goals: Gudjohnsen 69.
Ref: M Riley (W Yorkshire).