An unfortunate own goal was enough to send Swansea into the semi-finals of the Capital One Cup for the first time in their history, following a 1-0 win over Championship side Middlesbrough at the Liberty Stadium.
Sebastian Hines headed the ball into his own net from a Jonathan De Guzman corner in the 81st minute to send Michael Laudrup's side into the last-four.
Swansea join Aston Villa - 4-1 winners over Norwich - and Arsenal's conquerors Bradford in the semis, with Chelsea, who are currently in Japan at the Club World Cup, to play Leeds United for the final spot next week.
"It was a very tight game," Laudrup said. "It wasn't a brilliant game to watch for the neutral, but it was a tight cup game.
"Everybody had the right attitude, everybody wanted to win, but I think they wanted it too much (in the first half). When you want something too badly, you can't do exactly what you usually do.
"Middlesbrough put pressure on us, but in the second half we came out and played much, much better. We were more relaxed and took control of the game.
"For smaller clubs to go in and play a final or just to have that dream to go in and play that final, looking at the trophy waiting there for the winner, I think it's just fantastic.
"The great thing about Cup games -- especially when it's only one leg -- is that everything can happen.
"The greatest example of this we saw on Tuesday, a team from League Two beating a Premiership team -- and a big one. I think that can only happen in one-leg Cup games and it's great to see."
Middlesbrough manager Tony Mowbray, whose side beat Sunderland by a single goal in the previous round, was obviously disappointed to bow out in what he described as a "cruel" way.
"I thought it was a tight game that could have gone either way," Mowbray said. "On the count of chances I think we had the better of it, but that's football.
"We didn't allow Swansea to play their open, expansive play, and stifled them really well. The nature of the goal was cruel -- sometimes you don't mind losing to a good piece of play.
"Disappointing for us, but on another day in games like that we will come out on top. We have come to a team sitting in the top half of the Premier League and given a really good account of ourselves."
