WATFORD will travel to Villa Park for the FA Cup semi-final in positive heart after claiming an encouraging, yet unexpected, 4-2 victory over Portsmouth this afternoon (Monday).

Although the biggest league win of the season is highly unlikely to save the Hornets' Premiership skin, it will fuel hopes that they can cause a major upset against Manchester United who, ironically, Pompey beat just two days ago, and particularly if they can get Hameur Bouazza on the ball as much as possible.

The Frenchman was in superb form on his return to the starting XI, scoring twice, nearly completing a hat-trick and causing Harry Redknapp's defence countless problems whenever he attacked them. But there were plenty of other positives for Aidy Boothroyd as well, both individually and collectively.

Gavin Mahon and Tamas Priskin scored their first Premiership goals of the campaign, Clarke Carlisle came through his first outing this term unscathed, while the Hornets responded to their poor showing at Middlesbrough in exactly the right fashion and also came from behind to win in the top-flight for the first time this term.

Following the defensive horror show at the Riverside, Boothroyd was always likely to make changes and he didn't disappoint. Dan Shittu, Douglas Rinaldi and Darius Henderson, sporting a cast on his wrist, were left out, while James Chambers dropped to the bench, and in came Adrian Mariappa, Bouazza, Priskin and, following his injury nightmare, Carlisle for his first start of the season. There was more encouraging news on the injury front as Marlon King joined his team-mates for the pre-match warm-up.

Despite beating the Premiership leaders 2-1 on Saturday, Redknapp chose to make two changes to his starting line-up. Noe Pamarot replaced Lauren at right-back, while Lomano Lualua came in for Benjani up front.

There was a good natured start to the game, with former Hornet David James given a terrific ovation as he took his place in front of the Rookery, before he was greeted with chants of "England's number two" which received a smile and a thumbs up from the keeper.

Watford started the better and had their first opportunity in the fourth minute when a Jordan Stewart free-kick from the centre circle was flicked goalwards by Tommy Smith. The home side continued to pen Pompey back and had what looked a clear penalty appeal turned down in the tenth minute when Djimi Traore kicked the ball against the arm of Dejan Stefanovic, although referee Lee Mason was, in fairness, unsighted.

But the game became increasingly fragmented until the visitors took the lead in the 15th minute with another goal that was entirely preventable. Priskin needlessly gave the ball away to Sean Davis, who found Matt Taylor and the left-sided midfielder was given the time and space to advance to the edge of the D in a central area before curling a low right-footed shot past Ben Foster and in-off the base of the keeper's left-hand post.

The Hornets responded with Priskin forcing a save out of James but still looked to be lacking in self-confidence and energy until a decision went their way after 26 minutes. Priskin cut in from the right side of the area, beating Traore en route, but in trying to get back the Portsmouth defender only succeeded in taking away the right leg of the Hungarian. The referee rightly pointed to the spot and, after some deliberation, Bouazza calmly sent James the wrong way to net his sixth of the campaign and make it 1-1.

That goal gave Watford the spark they needed and an improvement in their performance followed, but they created little until Carlisle headed a Stewart free-kick from the right down and wide of James' near post two minutes before the interval. But the Hornets turned the game on its head a minute into injury-time.

Smith's superb cross from the right looked destined for the head of Priskin, but the danger seemed to have been averted when James punched the ball out towards the edge of the area. However, Mahon came onto the clearance without breaking stride and struck a fantastic left-footed half-volley that gave the Pompey keeper no chance as it flew past him to ensure the Hornets came from behind to take the lead for the first time this season.

That goal was Mahon's first of the campaign, and five minutes after the restart another Hornet broke his Premiership duck. Bouazza started the move, picking up the ball in his own half before breaking forward at pace and sliding in Steve Kabba to his left, and the striker instantly swept the ball across the area for Priskin to calmly side-foot past James and make it 3-1. The clearly delighted Hungarian then celebrated by dashing to the dug-out to shake hands with King.

After 57 minutes though, it really should have been 3-2. The ball was worked to Kanu in the area and he side-stepped the challenges of Mahon and Jay DeMerit and blasted the ball over Foster, only to see it rebound off the face of the bar. The Watford keeper then looked to have gathered the rebound, but dropped the ball, and Davis rifled in another shot from the right side of the six-yard box but Mariappa was in the right place on the line to nick it off the toes of Kanu.

Redknapp then made a double change, bringing on Niko Kranjcar and Rodolph Douala for Traore and Lualua, but Watford had another opportunity soon after when a lovely pass from Bouazza found Kabba on the edge of the area and the ball broke for Priskin. He managed to evade a couple of challenges to open up a shooting opportunity, only to see his effort deflected behind.

An even better chance came and went for the Hornets after 67 minutes. Smith was the orchestrator on this occasion, breaking from deep and spotting Bouazza in space on the left, but the Frenchman's shot was superbly kept out by James at his near post.

But the fourth goal did arrive in the 72nd minute and this time Bouazza was not to be denied. The utility forward played the ball into the feet of Kabba, who clipped a lovely ball back into his path before he was clattered from behind by Stefanovic. James looked like he had won the battle when he superbly kept out Bouazza's initial effort, but the youngster kept his head and fired in the rebound to net his second of an increasingly enjoyable afternoon.

Still Watford kept pressing, with Damien Francis sending an overhead kick straight at James after Carlisle had headed on a corner.

Arnold Mveumba replaced Davis after 80 minutes and within seconds of coming on the substitute had cut the deficit to 4-2. Gary O'Neil did well to reach the right byline before clipping the ball back to the substitute, who teed the ball up with his first touch and then dispatched an emphatic right-footed half-volley across and past Foster with his second.

Al Bangura was then introduced for Mahon, who had been injured in a challenge moments earlier, before Bouazza nearly completed his hat-trick in sensational fashion. A Stewart free-kick from the right was headed away to the edge of the area by Stefanovic and straight into the path of Bouazza, who connected with a stunning left-footed half-volley that whizzed a foot wide of James' right-hand post.

The striker was it again seconds later, sending a dipping right-footed attempt over the top, but Pompey were not far away from setting up a grandstand finish when Mveumba sent a cross-shot narrowly wide of Foster's far post after combining to good effect with Kranjcar.

After the fourth official had, incredibly, signaled five minutes of injury-time, Francis fired over the top, while at the other end Douala had a shot blocked and Kanu tamely struck the follow up at Foster.

The undoubted man-of-the-match, Bouazza, was replaced by Chambers and then Carlisle left the pitch to an equally warm standing ovation when Lloyd Doyley was given a late run out. The crowd scenes were replicated when the referee blew whistle.

Watford: Foster; Mariappa, DeMerit, Carlisle, Stewart; Smith, Francis, Mahon, Bouazza; Priskin, Kabba. Substitutes: Bangura for Mahon after 84 mins; Chambers for Bouazza after 90 mins; Doyley for Carlisle after 90 mins; Williams and Lee not used.

Portsmouth: James; Pamarot, Primus, Stefanovic, Traore; O'Neil, Davis, Hughes, Taylor; Lualua, Kanu. Substitutes: Kranjcar and Douala for Traore and Lualua after 59 mins; Mvuemba for Davis after 80 mins; O'Brien and Ashdown not used.

Bookings: None.

Attendance: 18,119 Referee: Lee Mason.