Blackburn's reward for trouncing the Divs is a tie with the winner of the Chelsea - Tottenham replay.
Ben Foster:
"There was always a chance this could happen and I would be gutted if it did and we end up playing United in the semi-final. But I can only get on with it.
"The Watford lads will not fear anything and if I make it through to Wembley it will be down to them.
"I've got mixed emotions. Don't ask me how I'll feel if we get them after the replay, it's bad enough knowing I might miss out in these circumstances."
The Times:
Ben Foster, the Watford and England goalkeeper, was described by Adrian Boothroyd, his manager, as a potential world No 1 after his role in Watford's 1-0 win over Plymouth Argyle in Sunday's quarter-final. However, the 23-year-old will miss the semi-final if United beat Middlesbrough in Monday's replay because he is on loan from Old Trafford. Watford have an agreement with United not to play Foster if the teams meet, so he is praying that his parent club are knocked out.
"The one downside of the possible game against United is that Ben would not be able to play," Gavin Mahon, the Watford midfield player, said. "I was speaking to him on the way back from Plymouth and he said he didn't mind who we drew, as long as it wasn't United.
"If we were to play United, I am sure Ben would be egging us on, even though he is their player. I expect he will be playing for England at the new Wembley before long, but it would be great if his first game there could be for Watford."
Will Manchester United and Chelsea do the treble - a hat-trick of fixtures against each other in one dramatic and climactic fortnight?
On May 9, the clubs are set to meet in what could be the Barclays Premiership title decider. After yesterday's draw, the two are favourites to meet in the FA Cup Final on May 19, and both are in the Champions League quarter-finals and have been placed on separate paths to the final in Athens on May 23.
Rooney determined:
"Obviously, we'd liked to have gone straight through, but the main thing is that we're still in the draw.
"It was disappointing to lose goals just before and just after half time, but it's a difficult place to come to get a result so we're pleased that, having gone behind, we fought back."
"We're all professionals and we have to keep going.
"I don't think [the extra game] is a problem and I'd like to play every game.
"We've got home advantage and we're confident of beating anyone coming to Old Trafford. It's getting towards the end of the season and everyone is thinking about finals and hopefully winning the league. I'm the same.
"It was a bad feeling losing to Arsenal. If we can get to the final again then I'm sure if we have that many chances again, we'll take them."
Watford chief executive Mark Ashton:
"Any draw in the semi-final is a good draw and we're delighted to be there. It's fair to say we are the team everyone wanted to play. We are delighted to be there and will be giving it our all. We have an agreement with Manchester United that Ben wouldn't play in any competition this season, so as far as we are aware that will stand."