Stephane Sessegnon's extra-time strike sent Sunderland into the FA Cup fifth round with a 2-1 win over Middlesbrough.
The in-form forward set up and finished the late winner, passing the ball to Connor Wickham and then getting it back, before shooting powerfully past 21-year-old goalkeeper Jason Steele.
Sunderland dominated possession for most of the match but their failure to make it count on the scoreboard kept the home side in the match and Middlesbrough ensured a tense finish when Lukas Jutkiewicz cancelled out Jack Colback's opener in the 57th minute.
Middlesbrough were under strength and had failed to win in the four games leading into the FA Cup fourth-round replay, but despite that poor form they had the best early chances of the match.
It was the visitors, however, that scored first at Riverside Stadium
In the 42nd minute, Fraizer Campbell knocked down a long aerial pass to Colback and the 22-year-old midfielder controlled the ball on his chest before crashing a left-footed half-volley into the goal off the underside of the bar.
Twelve minutes after the break Middlesbrough drew level when Jutkiewicz scored from just inside the box.
A deep cross from the right was headed down by Middlesbrough striker Curtis Main, under pressure from John O'Shea, and Jutkiewicz was first to the ball, shooting past Simon Mignolet's right hand into the bottom corner.
Sebastian Larsson almost gave Sunderland the lead in the 68th minute when he flicked Sessegnon's cross onto the post and four minutes later Phil Bardsley's powerful shot also hit the frame of the goal.
But the Premier League club had to wait until 112th minute for Sessegnon to make the difference.
Sunderland will face Arsenal at the Stadium of Light in the FA Cup fifth round on February 18.