Liam Miller's injury-time winner kept Sunderland on course for promotion with a hard-fought 2-1 victory over league leaders Derby.
A wonderful solo goal from Rams teenager Giles Barnes looked to have earned them a share of the points, but Miller rose to meet Grant Leadbitter's late cross, flicking it beyond Stephen Bywater at the far post.
The Black Cats had taken the lead through David Connolly's 27th minute penalty - Sunderland's first for over a year - but looked like rueing their failure to add to it in a first half they dominated.
Looking to strengthen their own play-off credentials, Roy Keane's side played with energy and invention in the first half, the latter something that was sorely missing from Derby's display before the break.
Sunderland had the first clear chance of the game in the 11th minute, Tobias Hysen cutting inside his man before sending a low shot flashing across the face of goal and just wide at the far post.
Derby failed to click up front with lone striker Steve Howard not getting the support that he wanted, and it was Sunderland who dominated.
But with chances hard to come by, the deadlock was broken from the penalty spot when referee Martin Atkinson spotted a tug on Connolly by Marc Edworthy.
It was Sunderland's first spot-kick in over a year, the last coming in the final minute of a 3-1 defeat to Aston Villa in November 2005, but Connolly showed no lack of practice, sending Bywater the wrong way for his 10th goal of the season.
Moments later Stern John almost doubled the lead in spectacular fashion, sending an overhead kick just wide from Danny Simpson's cross at the near post. Connolly went close again, nicking the ball off Edworthy in the area but seeing his shot deflect into Bywater's hands.
The Sunderland defence were holding Derby in check and goalkeeper Darren Ward, returning in place of Martin Fulop, was having a quiet afternoon.
Sunderland should have had a second with 10 minutes left in the half, but John - all alone five yards out - hit a tame shot at Bywater from close range.
Derby introduced Barnes for the start of the second half, hoping to put a little more spark in the attack.
It almost paid immediate dividends when the teenager got himself free inside the area, only to head over from Craig Fagan's cross with the goal gaping. Encouraged, Derby set about launching an all-out assault.
Howard, under close attention from Danny Collins, prodded a looping shot goalwards which Ward did well to tip over.
From the corner, Matt Oakley fired just over, and Howard then saw a header cleared off the line by Hysen. When it came, the equaliser was something special. Barnes picked the ball up on the edge of the area before breaking forward, beating two men with a quick spin before the firing through the legs of Nyron Nosworthy and beyond the helpless Ward.
The goal blew the game wide open but if anything it was too frantic, neither team able to create clear openings.
Connolly tumbled meekly under Darren Moore's challenge, but two penalties after a 16-month wait was too much to ask and he was instead booked for the dive.
Substitute Daryl Murphy thought he had restored Sunderland's lead in the 75th minute, but having created the angle for the shot, he saw his left-footed effort come back off the post with Bywater beaten. David Jones wasted a glorious chance for the visitors with 10 minutes left when he fired over from eight yards out after Barnes crossed.
At the other end, Murphy wriggled free of Moore to cross but could not pick out the unmarked Connolly. A minute later, Yorke burst through the middle but Bywater did well to save at his feet before Miller's dramatic late winner.
