WATFORD's hopes of reaching the FA Cup Final for the second time in their history ended this evening (Saturday) after they were convincingly beaten 4-1 by Manchester United at Villa Park.

Two goals from Wayne Rooney and singles for Cristiano Ronaldo and Kieran Richardson ensured the Premiership leader's passage into the Final was comfortable in the end, but for an hour the Hornets gave a good account of themselves and it would have been interesting if they'd managed to equalise for a second time.

It looked like Watford might be in for a torrid afternoon when Rooney emphatically fired in the game's first attempt to give United the lead inside ten minutes. Aidy Boothroyd's men steadied the ship though, and the superb Hameur Bouazza got them back on terms midway through the first-half. Crucially though, United were back in front within 90 seconds.

Bouazza almost did score again after the break, but Rooney's second was the clincher before Richardson applied the gloss.

Apart from their display in the first hour, the biggest plus for the Watford boss was the return of Marlon King. Last season's top scorer came off the bench late in the second-half to make his first appearance since October after being a shock inclusion in the 16.

Boothroyd was always going to have to make one change following the 4-2 victory over Portsmouth, with Richard Lee replacing the ineligible Ben Foster, but he also chose to bring in James Chambers for Steve Kabba, who had a slight injury. This meant that Tommy Smith switched to the left side of midfield, with Bouazza moving up front to partner Tamas Priskin. But the biggest news was the inclusion of King on the bench.

Sir Alex Ferguson, meanwhile, also made two changes to the team that so emphatically demolished AS Roma. Paul Scholes, who was suspended for the 7-1 Champions League victory, replaced Darren Fletcher, while Patrice Evra came in for John O'Shea.

United dominated possession in a quiet opening to the game but that all changed in the seventh minute when they took the lead in stunning fashion with their first attempt. The ball was played forward to the right angle of the area via a dummy from Alan Smith where Rooney stepped inside Adrian Mariappa and unleashed a fierce 20-yard drive that beat Lee at his near post, but such was the power of the shot it, in truth, gave him little chance. It was not the start Watford wanted.

Ronaldo headed a Ryan Giggs corner from the left behind soon after and then Lee had to move smartly to prevent Rooney latching onto an Alan Smith cross from the right after he dispossessed his namesake Tommy.

Alan Smith fired wide and high in the 12th minute as the Premiership leaders continued to turn the screw but five minutes later the Hornets had their first sniff of an opening when Tommy Smith's inswinging free-kick from the left was glanced on by Jay DeMerit but Alan Smith averted the danger by heading over his own bar.

Bouazza then had the Hornets' first shot of the game blocked before Scholes saw the same fate befall an attempt of his own at the other end. Bouazza tried his luck again moments later, cutting inside Gabriel Heinze before curling a left-footed attempt a yard wide of Edwin van der Sar's right-hand post from the edge of the area.

Watford though, were increasingly gaining a platform in the game and were back on terms after 26 minutes. A Gavin Mahon long throw from the right was not properly cleared, Tommy Smith was allowed the space to hook the ball back across goal with his right foot and Bouazza connected with a left-footed hook volley from ten yards that was deflected off Heinze over van der Sar and in-off the underside of the bar to make it 1-1.

But United should have regained the lead straight from the kick-off when Rooney got to the left byline and picked out Alan Smith in the six-yard box, but the striker inexplicably screwed the effort wide.

However, the Hornets' good fortune was to last less last than another 60 seconds. Rooney got away from Jordan Stewart with far too much ease and played a one-two with Alan Smith before advancing towards the near post and trying a shot, which deflected off Lee to present Ronaldo with the simplest of tap-ins to make it 2-1.

Watford almost responded immediately, with Mahon letting fly from 25 yards and van der Sar looking less than convincing in parrying the ball back out into the area, and then Damien Francis should have at least hit the target when presented with a free header from a Bouazza corner after 35 minutes but he put it wide of the far post.

United suffered a blow five minutes later when Rio Ferdinand was forced off with what looked to be a groin injury. Fletcher took his place and went to right-back, Evra switched across to the other side of the back four and Heinze moved into the middle to partner Wes Brown.

Francis had another, albeit more difficult, effort three minutes before the break when he met Tommy Smith's inswinging free-kick from the right with an angled header on the right side of the area but he was unable to direct it on target.

It then took a superb save from Lee, showing a strong hands, to turn a powerfully struck Rooney effort over the bar from ten yards after some neat interplay between the England striker, Alan Smith and Giggs. United forced a second corner from the initial set-piece which Fletcher glanced wide of the near post.

Rooney got an attempted lob wrong and Clarke Carlisle sent an ambitious and acrobatic effort high and wide before the half ended with United 2-1 to the good.

Watford made a positive start to the second period and their endeavour was almost rewarded in the 49th minute when Mahon's long throw from the left was helped on by Carlisle through a melee and Bouazza tried to ease the ball towards goal, but pushed it just the wrong side of van der Sar's right-hand post.

The excellent Frenchman then blazed another shot over before Rooney picked up the game's first card for going straight through Stewart after 52 minutes.

Watford continued to take the game to United and an edgy van der Sar had to arch his back to push away a dangerous Bouazza cross from beneath his own crossbar, but after 65 minutes United effectively booked their place in the Final. Giggs tried to thread Rooney through, but Carlisle made a fine tackle, clearing the ball to the right side of the area. However, indecision in the Hornets' defensive ranks gave Alan Smith the time to square the ball back across the area and Rooney was in the right place to net his second and make it 3-1.

Boothroyd responded by bringing on Kabba for Chambers but after 71 minutes Rooney could have completed his hat-trick following more unselfish work by Alan Smith, but he fired straight at Lee.

Michael Carrick was booked for a foul on Tommy Smith after 74 minutes, but then Lee came to Watford's rescue again, blocking an angled attempt from Giggs with his legs after the winger had turned Stewart inside out.

Ferguson made his second change after 77 minutes, bringing on Richardson for Ronaldo, but this was followed by a massive cheer from the Holte End when King entered the fray as a replacement for Priskin.

DeMerit was harshly booked two minutes later for supposedly pushing Alan Smith but if there was any doubt about the outcome, it was removed with seven minutes remaining. Alan Smith played a delightful ball down the inside left channel and Richardson broke free of the defence and calmly lifted the ball over Lee to make it 4-1.

Ole Gunnar Solskjaer was given a run-out for the closing stages when he replaced Giggs after the goal and then Lloyd Doyley came on for Mariappa.

Rooney had another opportunity to complete his treble in the last minute of injury-time after being slid in but Solskjaer, but blasted his right-footed effort wide of the near post. Tommy Smith then picked the England forward's pocket when he looked set to pull the trigger after Solskjaer and Alan Smith had both tried to tee him up.

Carrick was the last player to chance his arm before referee Howard Webb blew his whistle to confirm United's place in the Final.

Watford: Lee: Mariappa, DeMerit, Carlisle, Stewart; Chambers, Mahon, Francis, T Smith; Bouazza, Priskin. Substitutes: Kabba for Chambers after 69 mins; King for Priskin after 77 mins; Doyley for Mariappa after 87 mins; Bangura and Loach not used.

Manchester United: van der Sar; Evra, Ferdinand, Brown, Heinze; Ronaldo, Carrick, Scholes, Giggs; A Smith, Rooney. Substitutes: Fletcher for Ferdinand after 40 mins; Richardson after 77 mins; Solskjaer for Giggs after 83 mins; Cathcart and Kuszczak.

Bookings: Rooney for a foul on Stewart after 52 mins; Carrick for a foul on T Smith after 74 mins; DeMerit for a foul on A Smith after 79 mins.

Attendance: 37,425.

Referee: Howard Webb.