League One side Sheffield United have shocked Fulham to advance to the fifth round of the FA Cup by claiming a 1-0 victory at Craven Cottage.
Jamie Murphy came close to finding the net inside the opening two minutes, but saw his curling strike go wide of the post.
Muamer Tankovic was looking threatening for the hosts, and fired over a half-volley from the edge of the box.
The visitors were holding their own and Murphy came close when he was picked out at the back post, but headed his effort wide.
Dan Burn had a good chance to open the scoring at the end of the half, but saw his header following a corner go wide.
After the break Robert Harris tried his luck for the visitors with a long-range free kick that failed to trouble David Stockdale.
Tankovic continued to be his side's brightest spark and after cutting inside, he lashed a drive wide.
Steve Sidwell saw his low effort saved by Mark Howard, as the game finished level after 90 minutes.
John Brayford came closest for the visitors in the first period of extra time, but after a driving run into the box, he saw his strike pushed wide by Stockdale.
Pajtim Kasami drilled a strike over the bar, before seeing a stinging low effort tipped round the post by Howard.
In the final minute of extra time Sheffield United made the breakthrough, as Shaun Miller met Harry Maguire's header across the box to nod the ball in at the back post.
Sheffield United will now play the winners of the fourth-round replay between Nottingham Forest and Preston.