Chelsea had Frank Lampard red-carded but romped to victory at West Ham.
Ballack (centre) is mobbed by his team-mates after making it 3-0
Lampard's penalty after Salomon Kalou was fouled by Anton Ferdinand put his side ahead before Joe Cole angled in a precise shot for Chelsea's second.
Michael Ballack expertly half-volleyed in a third for the visitors, who had Lampard harshly red-carded for a push on Luis Boa Morte after 36 minutes.
Carlton Cole had a shot cleared off the line for West Ham but Ashley Cole's acute shot wrapped up Chelsea's win.
Blues boss Avram Grant had taken a swipe at the media in the run-up to the game, angry at negative coverage following the Carling Cup final loss to Tottenham.
And he showed little mercy with his team selection either as he made six changes to the starting XI.
The Blues should have been a goal up after two minutes when Nicolas Anelka had a goal incorrectly ruled out for offside.
The Frenchman thought he had scored when he slotted home after John Terry's header had been parried.
But Chelsea did not have long to wait to take the lead, with Hammers centre-back Ferdinand conceding a penalty for a trip on Kalou.
Lampard stepped up to send Robert Green the wrong way for the first of three Chelsea goals in the space five minutes.
Joe Cole added a second, showing fine control before firing a shot into the far corner of the net, before Ballack lashed home a low shot after being picked out by a Lampard cross.
Chelsea had virtually sealed victory over the Hammers with just 22 minutes on the clock, showing more fluency and attacking flair than in 120 minutes of action against Spurs.
The home side did manage to test Petr Cech, the goalkeeper tipping over a Mark Noble shot.
But Chelsea remained untroubled, even after Lampard was red-carded.
The midfielder tangled on the ground with Boa Morte and then pushed the winger after appearing to get caught by a kick.
Lampard (right) was red-carded after clashing with Boa Morte
Referee Peter Walton consulted his assistant before brandishing his red card and then booked Ballack for his part in the melee that ensued.
Another Noble strike was headed away as the home side tried to capitalise on their numerical advantage, but Chelsea held out until half-time.
West Ham struggled to create chances, but Carlton Cole must have thought he had scored when he dinked the ball over the on-rushing Cech only for Terry to clear off the line.
Ashley Cole then made it 4-0 when he sidefooted home from a tight angle after Joe Cole's shot had been parried.
The goal was the sign for Hammers fans to start trudging for the exit, their team emphatically beaten.
West Ham boss Alan Curbishley:
"It's a really bad day for us and we feel dreadfully disappointed for us and the fans.
"My players have done fantastically well this season. We have had major injury problems. I'm not going to criticise them."
On the red card he said: "I did see Frank push out but it was a soft dismissal."
Chelsea boss Avram Grant:
"We will do everything to do it (win the title). I never give in and I will not start now at my age.
"We started very well and if it was not a red card maybe the score would have been higher.
"I am very happy. The players showed fighting spirit and passion."
West Ham: Green, Neill, Ferdinand, Upson, McCartney, Faubert (Solano 66), Noble, Mullins, Ljungberg, Boa Morte (Ashton 46), Cole (Zamora 65). Subs Not Used: Wright, Spector.
Chelsea: Cech, Ferreira, Carvalho, Terry, Ashley Cole, Ballack, Makelele (Alex 84), Lampard, Kalou (Malouda 75), Anelka, Joe Cole (Essien 69). Subs Not Used: Cudicini, Drogba.
Sent Off: Lampard (36).
Booked: Ballack, Terry.
Goals: Lampard 17 pen, Joe Cole 20, Ballack 22, Ashley Cole 64.
Ref: Peter Walton (Northamptonshire).
BBC Sport Player Rater man of the match: Chelsea's Joe Cole 7.62 (on 90 minutes).
• Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.