Swans take no points from Premier League leaders
Two goals in the final 20 minutes saw the Swans beaten 3-1 at leaders Chelsea.
Antonio Conte's side were on top throughout, and took the lead in the 19th minute through Cesc Fabregas.
Despite having to deal with a large amount of pressure, the Swans grabbed a shock equaliser on the stroke of half-time through Fernando Llorente, who headed home his ninth of the season from Gylfi Sigurdsson's free-kick.
But Chelsesa were not to be denied victory and, after the Swans saw a big claim for a penalty turned down, the hosts struck twice to claim victory.
Pedro put them ahead in the 72nd minute as his shot squirmed under Lukasz Fabianski before Diego Costa wrapped up victory as the game entered the final stages.
Defeat left the Swans on 24 points from 26 games - four points above the relegation zone while third-bottom Leicester play Liverpool on Monday night.
The Swans made just one enforced change to the starting XI.
The only change to the side that beat defending champions Leicester City last time out saw Wayne Routledge take the place of Nathan Dyer, who was injured in the early stages of that game.
Federico Fernandez, who signed a new contract on Friday, partnered Alfie Mawson in defence with the latter having scored his third goal in six games during the win over the Foxes.
CHELSEA: Thibaut Courtois, Marcos Alonso, Cesc Fabregas, N'Golo Kante, Eden Hazard (Willian, 85), Pedro (Nemanja Matic, 76), Victor Moses (Kurt Zouma, 85), Diego Costa, Cary Cahill (capt), Cesar Azpilicueta, David Luiz.
SUBS: Asmir Begovic, Ruben Loftus-Cheek, Mitchy Batshuayi, John Terry.
SWANS: Lukasz Fabianski, Kyle Naughton, Federico Fernandez, Alfie Mawson, Martin Olsson, Jack Cork (capt), Tom Carroll (Jordan Ayew, 76), Leroy Fer, Wayne Routledge (Luciano Narsingh, 81), Gylfi Sigurdsson, Fernando Llorente.
SUBS: Kristoffer Nordfeldt, Angel Rangel, Jordi Amat, Leon Britton, Borja.
The first half was dominated by the hosts, who were in control of possession and territory as the Swans attempted to soal up the pressure.
There was an immediate signal of intent from Chelsea as Pedro fired over insiede the opening minute.
At the other end, the Swans saw a Jack Cork header from Gylfi Sigurdsson's corner drift wide, but that's as good as it got for Paul Clement's side in the opening 45.
Chelsea pushed and pushed, and the deadlock was broken after 19 minutes as Victor Moses found Cesc Fabregas inside the box, and the Spaniard controlled his cross before slotting into the far corner.
The Swans had to defend sternly to ensure the Blues' lead was kept to 1-0, and they did well to limit them.
It took a fine reflex save from Fabianski to prevent Fabregas from close range, while Martin Olsson came to the rescue to block Pedro's shot after a mazy run.
Then, with a second left of the half, the Swans stunned Stamford Bridge.
Sigurdsson's curling free-kick from 45 yards found Fernando Llorente, and the big Spaniard powered a sublime header into the top corner to level.
HALF-TIME: Chelsea 1-1 Swans
The second continued in the same fashion as the first, with Chelsea on the front foot.
It took a fine save low down by Fabianski to keep out the lively Eden Hazard, while goalscorer Fabregas was teed up by the Frenchman before seeing his thunderous effort cannon off the crossbar.
The Swans were having to deal with waves and waves of pressure, but they looked dangerous on the counter.
And they felt they had a great appeal for a penalty turned down after the ball struck Cesar Azpilicueta's hand as Sigurdsson worked his way into the box.
Referee Neil Swarbrick was unconvinced, though, and play continued.
It proved a vital call as three minutes later the hosts were back ahead.
Pedro cut inside from the right and his shot found the net after dipping below the hands of Fabianski.
The Swans needed a reply, but it never came.
The third goal of the game was crucial, and Chelsea found it.
Hazard jinked his way into the box and crossed for Diego Costa, and the striker tapped home to end the contest.