Manchester United booked their place in the first FA Cup final at the rebuilt Wembley Stadium when they beat Watford 4-1 in an entertaining semi-final at Villa Park on Saturday.

Two goals from Wayne Rooney and one each for Cristiano Ronaldo and Kieran Richardson secured United's path into the May 19 final, the first at Wembley since 2000, when they will face either Chelsea or Blackburn Rovers, who meet at Old Trafford on Sunday.

United, who will be appearing in a record 18th final, have won the competition a record 11 times and have now reached their eighth FA Cup final under manager Alex Ferguson.

The victory keeps them on course to win three trophies this season -- the Premier League title, the FA Cup and the Champions League -- and repeat the treble they achieved in 1999.

BLISTERING SHOT

Rooney put United ahead after seven minutes when he cut inside his marker, made space for himself and smashed home a blistering right-foot shot that left goalkeeper Richard Lee -- a diehard United fan as a child -- diving in despair.

Although United were largely in control, Watford replied with a surprising equaliser after 26 minutes when Hameur Bouazza latched on to a loose ball and volleyed it past van der Sar.

But the Hornets were only level for two minutes and were powerless to prevent United going back in front after 28 minutes with a typically forceful move and goal.

Rooney was the architect, storming down the right wing and outpacing the chasing defenders before attempting a shot that bounced back off Lee into the path of Ronaldo who swept the ball into an empty net from two metres out -- the perfect way to celebrate the new five year, 31 million pounds ($61.59 million) contract he signed this week.

Lee then kept Watford in the match with an outstanding save from a Rooney shot after an intricately worked move but the England striker was on hand for the third in the 66th minute when he turned in a low Alan Smith cross.

Rooney then had a couple of chances to become the first player since United's Alex Dawson in 1958 to score a hat-trick in a semi-final before Richardson completed a somewhat flattering scoreline in the 82nd minute, five minutes after coming on as a substitute.

The only blot on United's victory was when defender Rio Ferdinand aggravated a groin strain and had to go off late in the first half.