The Swans went down to a second consecutive defeat as Leicester City took a massive step towards the Premier League title following a 4-0 win at the King Power Stadium.
Francesco Guidolin's side fell behind after just ten minutes after Rihad Mahrez fired home from close range.
Leonardo Ulloa doubled their advantage when he headed past Lukasz Fabianski from a Danny Drinkwater free-kick.
It didn't get any better for the Swans either, with Ulloa sliding in the third on the hour mark.
Then substitute Marc Albrighton added a fourth and final goal with five minutes to play.
It was a well deserved victory for the Foxes, who are now closing in on the title following this victory.
Defeat left the Swans in 15th place on 40 points with three games left to play.
The Swans made two changes to the starting XI.
From the side that went down 3-0 at Newcastle, Leon Britton was recalled to midfield in place of Jefferson Montero while Wayne Routledge's inclusion meant Alberto Paloschi moved to the bench.
Leicester were without top-scorer Jamie Vardy due to suspension, meaning Leonardo Ulloa started in his place while winger Nathan Dyer - on loan from the Swans - was ineligible to face his parent club
LEICESTER CITY: Kasper Schmeichel, Danny Drinkwater, Wes Morgan (capt), Robert Huth, N'Golo Kante, Jeffrey Schlupp (Marc Albrighton, 82), Danny Simpson, Shinji Okazaki (Demarai Gray, 73), Leonardo Ulloa (Andy King, 79), Riyad Mahrez, Christian Fuchs.
SUBS: Mark Schwarzer, Daniel Amartey, Marcin Wasilewski, Ben Chilwell.
SWANS: Lukasz Fabianski, Angel Rangel, Federico Fernandez, Ashley Williams (capt), Neil Taylor, Leon Britton, Jack Cork, Leroy Fer (Jefferson Montero, ht), Gylfi Sigurdsson (Ki Sung-Yueng, 76), Andre Ayew, Wayne Routledge (Alberto Paloschi, ht).
SUBS: Kristoffer Nordfeldt, Kyle Naughton, Jordi Amat, Modou Barrow.
The hosts, leading second-placed Tottenham by five points going into this game, were exactly where they wanted to be after a flawless first-half.
Leicester, backed by a superb atmosphere at the King Power Stadium, were ahead after just ten minutes.
As the Swans were passing the ball around the back, Ashley Williams' attempted pass to Neil Taylor struck Riyad Mahrez and the Algerian cut back onto his left foot before firing low into the corner.
The home crowd erupted, and as the game hit the half-hour mark they were on their feet again.
Danny Drinkwater's inswinging free-kick found Leonardo Ulloa, and the big Argentinian shrugged off Williams before powerfully heading into the corner of the net.
The Swans were second best in all areas, and their best chance of the opening 45 minutes fell to Federico Fernandez, but he could only head over from Gylfi Sigurdsson's free-kick.
Sigurdsson then tried his luck with a dipping 35-yard free-kick, which Kasper Schmeichel had to scramble across goal to pad out for a corner.
That was the end of a miserable first 45 minutes for the Swans, who have it all to do in the second half.
HALF-TIME: Leicester City 2 Swans 0
The Swans made a double change at the break, with Jefferson Montero and Alberto Paloschi coming on in place of Leroy Fer and Wayne Routledge.
That was intended to give the Swans more attacking options, and they certainly looked brighter in the opening exchanges with Andre Ayew's header from an Angel Rangel cross dropping straight into Schmeichel's hands.
But any hope of a comeback was ended on the hour as Leicester grabbed their third.
Jeffrey Schlupp headed on Schmeichel's clearance, and when he raced on and saw his shot deflect back into his path, his low cross was slid in by Ulloa.
The home side were not content with that, however, and Fabianski had to be alert to get down to tip a powerful Schlupp effort wide for a corner.
Ayew then headed into the sidenetting before Fabianski was again called into action, with the Polish stopper denying substitute Andy King.
But he couldn't do anything to deny a fourth and final goal, with the keeper doing well to keep out Demarai Gray's effort before sub Marc Albrighton hammering home the rebound.