A late, late own goal by John Terry sealed Chelsea's fate, after they had made the best possible start.
Chelsea dominated the first half and in truth, had this being a boxing match, the referee would have stopped the bout for fear of Bolton taking too much punishment.
Chance after chance as a result of excellent possession play saw the Londoners peg Bolton deep into their own half.
Hernan Crespo should have done better when, on 11 minutes, a fine counter attack saw Claude Makelele feed the ball on the left, to Adrian Mutu.
The Romanian's cross into the box was met by Frank Lampard whose shot was blocked. It fell invitingly to Crespo, but the Argentinian's turn and shot went just wide.
Crespo did put the ball in the net three minutes later, but handled the ball in the process.
Mutu almost scored a sublime goal, but his run from the half way line and blistering shot was just inches wide.
Bolton's rearguard was eventually breached when Damien Duff's right-wing corner was headed on by John Terry into the gleeful path of Crespo, who unmarked stooped low from four yards out to head the ball into the net.
The expected goal charge did not occur and to Bolton's credit they hung on.
A disallowed goal by Ivan Campo after Kevin Nolan fouled Carlo Cudicini was a signal that Bolton would not lie down.
On 38 minutes, a cheap Makelele foul saw a Jay-Jay Okocha free kick, wide on the right, met beautifully by an unmarked Bruno N'Gotty, who powered his header past Cudicini.
Chelsea's title credentials were well and truly being tested and they failed to rise to the challenge.
The second half for the Londoners was a nightmare as Bolton took total control.
Lampard looked leg-weary as the Blues' midfield succumbed.
Bolton timewasted at every opportunity and the game was heading out for a draw when on 90 minutes substitute Henrik Pedersen skipped past Glen Johnson, wide on the left.
He slung in a low ball which agonisingly flicked off the right leg of defender John Terry and sailed past Cudicini.