Trailing 1-0 to a Frank Lampard goal, Sunderland found an 89th-minute equaliser courtesy of Fabio Borini before Ki Sung-Yueng’s goal settled the contest two minutes from the end of extra time.
Gus Poyet: “It was a matter of belief, a matter of knowing that sooner or later if you keep playing the same way you’re going to get the rewards.
“Credit to the players, they stuck by the plan and they believed in what we were doing and as soon as we started passing the ball a bit better we started creating the chances.
“Of course, we would like to score before but sometimes it’s even better to score at the end because it’s a different flavour.
“It was a typical cup game with goals right at the beginning of the second half, right at the end of the game and right at the end of extra time.
“I think it’s something important and something that is important for the fans because they find themselves in a semi-final.
“Now we’ll try to rest because it was a very big effort tonight and now we need to look forward for Saturday.”