BENNI McCarthy became the first Blackburn player in almost a decade to score 20 goals in a Premiership season as Rovers won this battle of the vanquished FA Cup semi-finalists.

The former Porto striker, who joined Blackburn for a bargain £2.5 million last summer, joined an exclusive club when he scored with a brilliant diving header past England goalkeeper Ben Foster on a night when Rovers rekindled their feint hopes of qualifying for Europe.

Chris Sutton was the last player to rack up 20 goals in a Premiership campaign for Blackburn when he achieved the feat in 1997/98, eventually finishing with 21 in all competitions.

Now, McCarthy is hoping to beat that mark during the remaining five games of the season, but even if he doesn't, the 29-year-old has still surpassed all expectations during what has been a remarkable first year in English football.

Brought in as a replacement for Craig Bellamy last summer, McCarthy has repaid the faith Mark Hughes showed in him, bagging 20 goals in 44 appearances in all competitions - a record that can only be bettered this term by the much vaunted quintet of Didier Drogba, Cristiano Ronaldo, Wayne Rooney, Frank Lampard and Peter Crouch.

Of McCarthy's 20 goals, 14 have come in the Premiership, and only four have come via the penalty spot, a statistic which perhaps best illustrates the impact he has made at his new club.

On top of that, the South African has also scored in 19 different games, and against 14 different opponents, Watford being one of five teams he has scored twice again this term.

Rovers were already leading 2-1, thanks to goals from Chris Samba and the rejuvenated Jason Roberts inside the first 10 minutes, when McCarthy flung himself at a sumptuous David Bentley cross and sent a diving header sliding past Foster into the far corner.

A delighted Hughes said: "Benni's had a fantastic season and I enjoyed watching him work with Jason Roberts tonight.

"Twenty goals is a great achievement, even for an established Premier League player, who has played numerous seasons at this level.

"But Benni has done it in his first season here. He's a player of quality and he will always score a goal.

"It was great delivery, in fairness, from Bents, which is a big factor in our play at the moment.

"But Benni is a goalscorer and he's more than capable of getting on the end of things like that."

McCarthy and Roberts ripped Watford to shreds at times here, and had Rovers not taken their foot off the gas in the second half, they would surely have run up a cricket score.

Determined to erase the disappointment of Sunday's FA Cup semi-final exit at the hands of Chelsea, Rovers needed just seven minutes to unlock a flimsy Watford defence.

Bentley whipped over a corner from the left and Samba, who was inexplicably unmarked at the back post, planted a firm header past England goalkeeper Ben Foster from inside the six-yard box: 1-0.

The celebrations had barely died down on the Blackburn End before Foster found himself fishing the ball out of the back of his net again.

Bentley was again the provider, this time lifting a clever ball over the top of the Watford defence, leaving Roberts in a straight foot race with Clarke Carlisle.

As the pair entered the box, the in-form Rovers striker managed to barge past his opponent before beating Foster with a scuffed right-foot finish: 2-0. And barely 10 minutes on the clock.

By now, Rovers were in cruise control and Morten Gamst Pedersen thought he had made it 3-0 in the 18th minute when he pounced on a fumble from Foster, only to discover that he had strayed off-side.

Watford briefly threatened to make a game of it when they pulled a goal back in the 21st minute from their first meaningful attack.

Hameur Bouazza created a yard of space for himself with a neat pirouette on the right-hand side of the area and then promptly delivered a pin-point cross to the far post, where the Brazilian Douglas Rinaldi towered above Ryan Nelsen to power a bullet header into the roof of Brad Friedel's net: 2-1.

However, that goal merely sharpened Rovers' focus, and they carved the Hornets open once more in the 32nd minute.

Again, the outstanding Bentley was the architect. The England hopeful completely deceived Gavin Mahon with a nifty piece of footwork on the right touchline, and then curled a delightful cross towards the penalty spot, where McCarthy was lurking: 3-1. Game over.

From then on, it became an exercise in damage limitation for Watford as Rovers threatened to run riot.

Pedersen warmed Foster's fingertips with another stinging low drive following a cleverly worked short corner routine. Then Samba and Aaron Mokoena both got in each other's way in their eagerness to convert another set-piece delivery at the far post.

Watford manager Aidy Boothroyd threw on Steve Kabba at the beginning of the second half, and the former Sheffield United man made an immediate impact, unleashing a venomous drive from distance that drew a full-length save from Friedel.

But that was about all the visitors could muster.

With the points safely in the bag, Rovers took their foot off the pedal, but McCarthy should have made it 4-1 in the 69th minute.

Roberts unselfishly played him in but, with only Foster to beat, he screwed his effort harmlessly wide of the near post. Not that it mattered. The damage had already been done.