Stephane Sessegnon's extra-time strike secured a 2-1 win over Middlesbrough as Sunderland booked an FA Cup fifth-round clash with Arsenal in dramatic style.
The Benin international blasted home a 112th-minute winner to send the Barclays Premier League side through after being pushed all the way by their npower Championship neighbours.
Jack Colback had given the visitors the upper hand in the fourth-round replay with a fine 42nd-minute strike, but Lukas Jutkiewicz's first goal for Boro ensured an extra 30 minutes was required.
The Teessiders eased themselves into the game and as the half wore on, it was they who created the better chances. But just as Boro sensed they were gaining the upper hand, the visitors hit back in devastating style.
Fraizer Campbell, back in the starting line-up after being rested at the Britannia Stadium did well to lay off a 42nd-minute long ball into the path of Colback, who controlled instantly before smashing a left-foot volley home off the underside of the bar.
Sunderland returned knowing a second goal might effectively seal their passage, and they might have got it within 10 minutes when defender Michael Turner headed James McClean's near-post cross over.
However, it was Boro who dragged themselves back into the tie with 57 minutes gone. Jutkiewicz was first to react to a loose ball inside the penalty area, then planting a firm right-foot shot past Simon Mignolet to level.
The Sunderland keeper was relieved to clutch Tony McMahon's volley to his midriff four minutes later, before opposite number Jason Steele was tested much more rigorously by Craig Gardner's swerving right-foot strike.
Steele beat away a well-struck Phil Bardsley effort with 11 minutes left on the clock and the game went into extra-time.
Boro looked the more threatening as the extra 30 minutes started, but their fate was sealed in the 112th minute when Sessegnon drilled home from 15 yards after the ball broke to him to snatch victory for Sunderland.