London - Chelsea were denied a club-record 24-game unbeaten run as Papiss Cisse's second-half double earned Newcastle United a stunning 2-1 win over the Premier League leaders on Saturday.
For the second successive weekend, Jose Mourinho's side struggled in the northeast, as Alan Pardew's Newcastle recorded a third consecutive home win against the title favourites.
Defeat prevented Chelsea from going nine points clear at the league summit and presented Manchester City with an opportunity to trim their lead to three points ahead of their home game against Everton.
Newcastle appeared to have been fired up by Mourinho's pre-match assertion that they seem to save their finest performances for matches against the west London side.
They elected not to adopt the ultra-defensive tactics employed by their neighbours Sunderland, who had held Chelsea to a 0-0 draw last weekend, and were rewarded as Cisse came off the bench to score twice.
A late Didier Drogba effort ensured a nerve-wracking final seven minutes -- plus six minutes of added time -- for the hosts, who lost defender Steven Taylor to a second yellow card.
It proved a memorable debut for Jak Alnwick, Newcastle's third-choice goalkeeper, who came on as a half-time substitute for the injured Rob Elliot.
The 21-year-old produced a wonderful finger-tip save late on to deny an out-of-sorts Diego Costa as Pardew's side held on for a famous victory to mark the manager's impending fourth anniversary in charge.
The visitors could have been three goals up before Newcastle mustered their first attempt on goal, with Thibaut Courtois blocking a close-range effort from Jack Colback after neat approach play from Ayoze Perez.
Newcastle's strong finish to the first half was in contrast to most of what had gone before, as Chelsea dominated, but failed to make their superiority pay.
Taylor, restored to the hosts' back four along with skipper Fabricio Coloccini, twice produced last-ditch blocks to deny Costa and Eden Hazard, as some of Newcastle's defensive work bordered on the desperate.
Chelsea centre-back Gary Cahill headed wastefully over from a Fabregas corner, and Willian fired two good openings narrowly wide.
Soon after, Willian went even closer with a curling left-foot effort when Hazard's cross evaded Costa to fall nicely for the Brazilian 18 yards from goal.
Oscar also went close shortly before half-time with an improvised overhead kick that flashed narrowly wide of the right-hand upright.
Half-time failed to halt Chelsea's forward momentum, and Mikel should have scored when he headed wide from a Fabregas free-kick.
Newcastle responded by taking a 57th-minute lead thanks to Cisse's sixth goal of the season.
The Senegal international had been on the pitch for barely four minutes when Cahill failed to cut out a low cross from Sammy Ameobi, allowing the substitute a simple finish from close range.
Moussa Sissoko ought to have doubled the lead within a minute as Chelsea failed to deal with a Colback corner, but the Frenchman, restored to the team after suspension, headed over.
Newcastle rode their luck after taking the lead, with Alnwick saving from Andre Schurrle before Hazard hit the post.
They were rewarded for their dogged defending when they claimed the contest's crucial second goal with 12 minutes left.
Referee Martin Atkinson played an excellent advantage, allowing Colback to release Sissoko despite a foul by Fabregas.
Sissoko looked to have lost possession as he surged into the area, but managed to poke a pass through to Cisse, who made no mistake from 12 yards.
Substitute Drogba ensured an anxious final seven minutes, as he beat Alnwick to head home a Fabregas free-kick awarded for Taylor's lunge at Schurrle that earned the Newcastle captain a second yellow card.
But Chelsea failed to make their numerical advantage pay, with a late barrage failing to revive their dream of emulating Arsenal's 2003-04 team by going an entire season without defeat.