The nine-man Swans bowed out of the FA Cup as they suffered a 3-1 defeat at Blackburn Rovers.
Garry Monk's side were reduced to 10 men after just six minutes as referee Craig Pawson showed Kyle Bartley a red card for bringing down Josh King.
But despite their man disadvantage, they took the lead at Ewood Park thanks to Gylfi Sigurdsson's stunning 25-yard strike.
The lead lasted just two minutes, however, as Chris Taylor fired past Lukasz Fabianski from close range after Tom Cairney had nodded down Marcus Olsson's cross.
Blackburn would go on to book their spot in the fifth round as sub Rudy Gestede poked home following a corner and Craig Conway's shot squirmed under Fabianski late on.
And things got worse for the Swans when referee Pawson dismissed Sigurdsson in added-on time following his challenge on Taylor.
Rovers defender Matt Kilgallon struck a long ball over the top of the Swans defence for King to chase, and when he went down following contact with Bartley, Pawson showed the centre-back red.
From the free-kick some 20 yards out, Fabianski parried Cairney's effort before King poked the loose ball wide from eight yards.
Swans boss Monk immediately made a change as Federico Fernandez replaced Tom Carroll to restore a four-man defence.
King looked lively for Blackburn, and his trickery inside the visitors' box teed up Cairney, but Fabianski collected the danger.
But the Swans took the lead after 20 minutes with a stunning strike from Sigurdsson. He cut inside from the left before firing a thunderbolt into the top corner.
The celebrations in the away end had barely settled down before the hosts were back on level terms two minutes later.
Olsson's cross was nodded down by Cairney at the back post, and Taylor controlled before shooting on the turn past Fabianski from eight yards.
The Swans looked to regain their lead soon after as a surging run by Sigurdsson led to Dyer seeing two efforts blocked inside the box.
Blackburn were then forced into a change as David Dunn replaced the injured Lee Williamson.
And, just before the break, Bafe Gomis failed to fully connect with Dwight Tiendalli's cross after he had latched onto Jordi Amat's fine through ball.
Both teams managed to carve open opportunities in the opening exchanges of the second half.
Gomis saw his powerful effort blocked by Shane Duffy and then King's trickery saw him beat Fernandez before Fabianski snuffed out his cross.
Cairney spurned a decent chance when David Dunn found him inside the box, with the midfielder firing well off target.
Both sides made a change at the hour mark as Blackburn introduced Gestede in place of the lively King while, for the Swans, Jefferson Montero came on for Barrow.
And after further substitutions it was Gestede who edged Blackburn ahead when he poked home from close range after he took advantage of a quickly-taken corner in the 78th minute.
The Swans needed a quick response and they almost got it as Sigurdsson's pass into the box for Angel Rangel split the Blackburn defence open, but Duffy's perfectly-timed challenge denied the Spaniard.
Sub Nelson Oliveira, on for Gomis, then drove straight at keeper Simon Eastwood after Montero's pass had been flicked into his path by Sigurdsson.
But Blackburn booked their place in the fifth round after Conway's dipping effort squirmed under Fabianski and rolled over the line in the 89th minute.
And things got even worse as Sigurdsson was dismissed for a challenge on Taylor.
BLACKBURN: Simon Eastwood, Adam Henley, Matt Kilgallon, Jason Lowe (capt), Josh King (Rudy Gestede, 59), Tom Cairney, Marcus Olsson, Lee Williamson (David Dunn, 40; Jordan Rhodes, 76), Chris Taylor, Shane Duffy, Craig Conway.
SUBS: Jason Steele, Ben Marshall, Grant Hanley, Chris Brown.
SWANS: Lukasz Fabianski, Angel Rangel (capt), Kyle Bartley, Jordi Amat, Dwight Tiendalli, Tom Carroll (Federico Fernandez, 8), Jonjo Shelvey, Gylfi Sigurdsson, Nathan Dyer, Modou Barrow (Jefferson Montero, 61), Bafe Gomis (Nelson Oliveira, 76).
SUBS: Gerhard Tremmel, Kyle Naughton, Jay Fulton, Marvin Emnes.