Chelsea had a great chance to close the gap on leaders Arsenal, but fluffed their lines as the strikers failed to capitalise on numerous chances and then went down 3-2 to Stoke City with a last-gasp killer goal.
Several gilt-edged changes in the first half were squandered as they failed to capitalise on Andre Schurrle's 10th minute opener.
Three minutes before the break, Stoke equalised with their only shot on goal through Peter Crouch.
That should have been the walk-up call they needed, but it was ignored and Chelsea went behind soon after the restart through substitute Stephen Ireland. But the Blues responded in kind and Schurrle smashed home a fine shot from the edge of the Stoke penalty area.
More chances were wasted by the Londoners, and to his credit Jose Mourinho sent on strikers Demba Ba and Samuel Eto'o in search of the winner.
But naive defending in midfield allowed the home side to break through and Oussama Assaide rifled home an unstoppable but preventable last-minute goal that sealed the Londoners fate.
It was a good start for the Blues, winning a corner in the first minute showed their intent from the off.
But Stoke, managed by ex-Chelsea favourite Mark Hughes have proven themselves in the past to be a tough nut to crack and powerful on the counter-attack.
The visitors should have taken the lead on five minutes when Andre Schurrle picked up a misplaced pass and raced clear on the right. His byline cross was perfect for the in-running Ramires, who mistimed his right-footer and skied the ball over goalkeeper Asmir Begovic's crossbar from six yards out.
But the Blues would not be denied, and on 10 minutes they went ahead through the German international Schurrle.
Picking the ball up from Mikel, the wideman first jinked to his right, then his left, before planting a firm left-footer from the left hand side of the edge of the Stoke City penalty area across the path of the diving Begovic into the bottom left hand corner on his net.
Mata then had a shot from just outside the area, this time it was well held by the Stoke goalie.
Charlie Adam lasted just 19 minutes. Having told the media midweek how tough he and his side were going to mKe it for the Blues, the ex-Liverpool midfielder was helped off the pitch having first suffered an injury and then, while trying to shrug it off, had the ignominy to be hit on the back by his own player Jonathan Walters's albeit fearsome shot. Stephen Ireland replaced him.
Fernando Torres was a whisker away from doubling the Londoners' lead on 25 minutes, when a quick counter from Mata saw the ball in he'd to Eden Hazard on the left. the Belgium's caressed ball into the path of Torres was a shade too far for the Spaniard and the ball drifted away from danger.
While only 1-0 and with missed chances behind them, Chelsea had to be careful and on 36 minutes they had a lucky escape when a deep ball was fed into the Chelsea area. Thankfully it fell to Walters and not beanpole Crouch. Cech was alert to the downward header close to his left-hand post and snuffed out the effort.
But the Blues did not learn and from a corner, with four minutes of the half to go, they equalised.
Cech came out to meet the crossed ball, but misjudged the deep flight of it and was caught on his six-yard line.
The ball continued over him and fell to the feet of Crouch, who took one touch before squeezing the ball into the back of the Chelsea net - their only shot on target so far.
Neither side made any changes in personnel at half-time.
Stoke started the second half on the front foot, pausing the Blues into a rearguard action and they got their reward five minutes in.
From a kick out from Begovic, the ball fell to Walters who out-muscled Mata on the right. He fed an unchallenged Ireland, who on the edge of the Chelsea area, curled an exquisite left-footer past Cech and into his right hand corner of the net.
But the Blues, shaken from their half-time cup of tea, pulled the level three minutes later.
A Mata free-kick from 35 yards out was seemingly headed clear. But Stoke did not take into account the left boot of Schurrle who arrowed a daisy-cutter through their defence and past Begovic from 20 yards.
Schurrle almost hit his third three minutes later, when he curled a brilliant ball from the edge of the Stoke penalty area towards goal, but it rattled off Begovic's crossbar and cleared.
Torres left the pitch, sprinting - perhaps the most exercise he had all game, to be replaced by Demba Ba on 60 minutes.
Quote how Ireland failed to give the home side the lead on 68 minutes is anybodies guess.
With the Blues defence left exposed once again, Crouch had the simple task of chesting the ball down to Ireland, free in the six-yard box. The midfielder did the first bit of trapping the ball correctly, but fluffed the second bit by sling the ball over Cech's crossbar.
Jose Mourinho, sensing perhaps the tide of the game could go against them, and in clear need of three points to get closer to leaders Arsenal, replaced Mikel and Schurrle with Frank Lampard and Samuel Eto'o with 70 minutes on the clock.
A possible penalty for Ba, a clever dink just wide by Eto'o and a possible foul on Eto'o in the Stoke penalty area by Ryan Shawcross , all in the space of five minutes could have sent the game
Chelsea's way. However referee Jonathan Moss decided otherwise.
Lampard had a free kick saved by Begovic with 10minutes to go. The temperature in the ground dipped but it was raised in the pitch as tempers flared as challenges went in strong and sometimes late.
Peter Crouch, John Terry, on his 33rd birthday and Cesar Azpilicutea all entered Moss's book as the clock ticked down.
But with seconds left, the Blues were undone in spectacular fashion, albeit of their own making.
Trying to make a quick counter-attack, the Blues were quickly shut down. The ball was sent wide on the left to substitute Qussama Assaide who took three touches before letting fly with a blistering right-footer from 20 yards, which this time at least, Cech could do nothing about, and the ball ripped past Cech and into the top left hand corner of his net.
Teams: Chelsea Cech, Ivanovic, Cahill, Terry, Azpilicueta, Ramires, Mikel, Schurrle, Mata, Hazard, Torres
Subs: Schwarzer, Cole, Essien, Lampard, De Bruyne Ba, Eto'o
Stoke City: Begovic, Cameron, Shawcross, Wilson, Muniesa, Arnautovic, Nzonzi, Whelan, Adam, Walters, Crouch
Subs: Sorensen, Pennant, Palacios, Jones, Assaidi, Wilkinson, Ireland
Referee : Jonathan Moss