Hameur Bouazza scored the only goal of the game at Home Park yesterday before the Barclays Premiership strugglers withstood a barrage of attacks from their Coca-Cola Championship opponents.

After avoiding an upset, the Hornets earned a place in the hat among teams such as Manchester United and Chelsea, reverting to their role as underdogs.

"Everybody will want us in the draw," said Boothroyd. "That's fine and perhaps we can use that."

Ben Foster, who Boothroyd has loaned from United, kept Watford ahead with a string of fine saves, prompting his manager to tip him to become the finest goalkeeper in the world.

"Ben Foster underlined why I think he will be the world's number-one goalkeeper," said Boothroyd.

Foster's best saves came from a Kevin Gallen free-kick and a late effort from Lilian Nalis, which would have sent the quarter-final to a replay.

The keeper was booked in the second half for time-wasting as the Hornets managed to hold on for victory.

"He's ruined my dream with some great saves," said Plymouth boss Ian Holloway.

"He's cracked my heart.

"We threw everything at it - kitchen sink, golf clubs. We emptied the garage and threw it at them but it wasn't enough. At least my garage is tidy."

The victory puts Watford within sight of Wembley, which could earn a European place depending on this year's finalists.

"I'm thrilled," added Boothroyd.

"We've taken knocks this year and haven't had luck in the league but we've had it in the FA Cup. I'm delighted to be in the semi-finals.

"It keeps it bubbling and keeps the momentum. It's a credit to the players that they kept going - we've got to because you never know."