The Swans went down to a 3-2 defeat to Tottenham Hotspur in a closely-fought encounter at White Hart Lane.
The hosts took the lead after just seven minutes at White Hart Lane, with Nacer Chadli perfectly directing a Danny Rose cross beyond Lukasz Fabianski.
The Swans then saw Bafe Gomis stretchered off after fainting in an off-the-ball incident. However, the French striker was later given the all-clear after being examined by the club's medical staff.
The Swans were level not long after, with Ki Sung-Yueng firing through Hugh Lloris' legs from an acute angle.
But Tottenham made sure of the points in the second half, with Ryan Mason firing them back into the lead five minutes after before Andros Townsend's fine solo run and finish made it 3-1.
But when Gylfi Sigurdsson volleyed home from sub Jefferson Montero's cross in the 88th minute, it set up a tense finish.
The Swans, though, couldn't find an equaliser in the three minutes of added time as Hugo Lloris made a superb stop late on to deny Federico Fernandez.
This defeat left the Swans on 40 points from 28 games, with Garry Monk's men moving down a place to ninth.
The Swans made one change from the 1-0 victory at Burnley. Gylfi Sigurdsson returned from injury to face his former club, replacing Tottenham loanee Tom Carroll, who was ineligible to play against his parent club.
SPURS: Hugo Lloris (capt), Kyle Walker, Erik Dier, Jan Vertonghen, Danny Rose (Ben Davies, 77), Nabil Bentaleb, Ryan Mason, Andros Townsend (Mousa Dembélé, 64), Christian Eriksen, Nacer Chadli, Harry Kane (Roberto Soldado, 75).
SUBS: Michel Vorm, Vlad Chiriches, Erik Lamela, Paulinho.
SWANS: Lukasz Fabianski, Kyle Naughton, Federico Fernandez, Ashley Williams (capt), Neil Taylor, Jack Cork, Ki Sung-Yueng, Jonjo Shelvey (Jefferson Montero, 72), Gylfi Sigurdsson, Wayne Routledge, Bafe Gomis (Nelson Oliveira, 11).
SUBS: Gerhard Tremmel, Angel Rangel, Jordi Amat, Leon Britton, Marvin Emnes.
The game was only seven minutes old when Tottenham took the lead.
Danny Rose crossed from the left and Nacer Chadli volleyed beyond Lukasz Fabianski and inside the far post.
Things got worse for the Swans as just before the game restarted, Bafe Gomis was stretchered off after going down off the ball. Nelson Oliveira came on in his place.
The Swans needed an instant response, and they got back on level terms after 20 minutes.
After Gylfi Sigurdsson's goal-bound free-kick was padded out by a fantastic one-handed save by Hugo Lloris, the ball was worked back to Neil Taylor, whose fine penetrative pass into the box found Ki Sung-Yueng, and the South Korean slid through the keeper's legs from the acutest of angles.
Tottenham were enjoying the better possession and territory, and looked to test the Swans with a number of crosses, but the visitors dealt well with the threat.
Ryan Mason then drove low at Fabianski, which the keeper did well to collect, before Kyle Naughton struck a volley wide following some nice build-up play.
Tottenham then went within inches of retaking the lead as Christian Eriksen's inviting cross was swatted wide by Fabianski, and the keeper came to the rescue once again as he denied Nabil Bentaleb, who tried his luck from 20 yards.
The teams then saw out six minutes of added time before referee Michael Oliver blew for half-time.
HALF-TIME: Tottenham 1 Swans 1
The Swans made the first attack of the half as Jonjo Shelvey's thunderous 20-yard effort was palmed over for a corner by Lloris.
Harry Kane then nodded wide before the hosts took the lead after 50 minutes through Mason, who drilled into the top corner after latching onto a pass inside the box.
And Tottenham doubled their lead ten minutes later through Andros Townsend, who raced on from inside his own half and into the Swans box before turning inside onto his right foot and curling beyond Fabianski from ten yards.
The hosts weren't happy to settle at that either, and Kyle Walker's roving run ended with his 15-yard effort being deflected wide for a corner.
Mauricio Pochettino then changes as Townsend, Kane and then Rose were replaced by Mousa Dembele, Roberto Soldado and Ben Davies while the Swans introduced Jefferson Montero in place of Shelvey for the last 18 minutes.
And Soldado went close to making an instant impact as he met a cross into the box, but his header dropped just wide of the far post.
The visitors gave themselves hope with two minutes to play as sub Montero crossed to the unmarked Sigurdsson, who volleyed home from close range.
The Swans continued to push in a thrilling three minutes of added time, and Lloris had to be at his best to deny Federico Fernandez's header following another Montero cross.
But Tottenham held on for the victory, which ended the Swans' run of two consecutive victories.