UNITED were dumped out of the FA Cup on their own patch by arch rivals Leeds. Jermaine Beckford's first-half goal sent Leeds into dreamland at Old Trafford. The in-form striker's 20th goal of the season was enough to dump United out of the competition. On their first visit for nearly six years, the League One side clinched their first win at the home of their bitter rivals since 1981 and it was greeted with unbridled joy by a 9,000-strong travelling army. The hosts suffered an early blow when Nemanja Vidic was injured in the warm-up, so Wes Brown stepped up from the substitutes' bench to partner the returning Jonny Evans in central defence. Leeds made a spirited start and Bradley Johnson had an opportunity to pick out the in-form Jermaine Beckford but squandered it. However, he did manage to force Gary Neville into conceding a corner that Tomasz Kuszczak had to punch away under pressure. Beckford hooked a volley over, then Anderson fouled Johnson, only for Andy Hughes to drift his free-kick straight to Kuszczak. Beckford collected Neil Kilkenny's short pass and curled another effort towards the home goal that Kuszczak saved comfortably. Obertan's chipped cross was too near Casper Ankergren after he had been released by Welbeck, then the Frenchman misdirected a cross to the young striker as Berbatov screamed for a cut-back. Anderson screwed a shot wide as the Premier League champions began to exert their authority. However, Leeds were still a threat, as they proved after 19 minutes when Welbeck lost possession inside the visitors' half and Jonathan Howson launched a long ball over the top for Beckford to chase. The striker got half a yard on Brown and, although his first touch appeared too strong, Kuszczak was slow to react and Beckford turned the ball into the United net as the Pole raced out. On the touchline, Leeds boss Simon Grayson was ecstatic. However, his joy would have lasted only five minutes if Jason Crowe had not scampered back to clear off the line after Wayne Rooney had sprung the Leeds offside trap and raced forward into the visitors box before sliding a shot underneath Ankergren. Leeds were performing heroically and Johnson floated a header wide of the far post after Crowe had charged forward on the overlap. Rooney curled a shot wide at the other end after Obertan had won the hosts a corner. The England star was trying to spark his team into life and he set up Welbeck for a shot that sailed narrowly wide from an acute angle. Brown was booked for chopping down Luciano Becchio inside the Leeds half after Obertan had been caught in possession. Ferguson could not have been impressed with his side's efforts. Gibson's square ball under no pressure summed up the half. The Irishman was way off target as he tried to find Neville. The veteran defender still managed to reach the ball, only to see it roll out of play as he tried to control. Brown's thundering challenge on Johnson triggered an angry reaction, with Grayson arguing with Neville at one point.Leeds had the first attack of the second half as Howson curled over a cross that Kuszczak cut out. Ferguson had resisted the temptation to make changes at the interval and could have been rewarded with a penalty when Welbeck was seemingly blocked off in the box by Howson, only for referee Chris Foy to wave play on. There was even more friction now though. Howson and Gibson were picked out for a lecture for a scrap close to the home area that had started when Brown went in on the Leeds man. Ankergren saved superbly to deny Welbeck, who had raced into the box. He then did even better to block a close-range Berbatov effort. Gibson was booked for a late tackle on Johnson, and Naylor was also shown a yellow card when he cynically hacked down Rooney. Brown, who was treading a very fine line, barged into the back of Beckford, although Leeds could make nothing of the free-kick. Ferguson introduced Ryan Giggs and Antonio Valencia for Welbeck and Obertan just before the hour mark. Leeds had been a muted attacking force for quite a while but Johnson let fly with a speculative blast that Kuszczak saved easily. Fabio Da Silva strode onto a Rooney lay-off and curled a shot narrowly over the top. Johnson went for goal with a 25-yard free-kick but Kuszczak gathered at the second attempt. Michael Owen was the next man on, for Anderson, and both he and Berbatov had a chance to finish off Valencia's cut-back before Rooney blazed over. Ankergren saved low from Rooney, who then fired over when well placed to do much better after Valencia had again created space. Leeds were not totally reliant on defence, though, and Beckford came agonisingly close to sealing their place in the fourth round 12 minutes from time. Robert Snodgrass came even closer shortly afterwards when his free-kick shook the angle of bar and post with Kuszczak beaten. The pace was unrelenting and Owen thought he should have had a penalty when he went down under Hughes' challenge but Foy was unmoved. Five additional minutes must have shredded a few nerves among the Leeds supporters. But after so many dark days, this was to be one of glory. Rooney wasted the last chance as he drove his shot wide.