Eugene Laverty broke his World Superbike duck in emphatic fashion as he powered to a double victory at Monza this afternoon.

The Yamaha rider took an unflustered maiden WSBK win in race one before benefiting from a penalty handed to long-time leader Max Biaggi in race two.

Championship leader Carlos Checa suffered a difficult day, finishing ninth and 10th on his Althea Ducati as his lead in the overall standings was reduced to 27 points by Laverty's team-mate Marco Melandri.

Laverty is up to fifth place on the back of his perfect result.

Laverty took the lead in race one at the start of the second lap and had a tough task to fend off the attentions of Biaggi's Aprilia, who had the edge on the straights and put the Yamaha under intense pressure.

But Laverty had the advantage into the braking zones and repelled the reigning champion time and again, while Biaggi's threat finally receded when a string of errors saw him lose time that he was unable to recover.

Biaggi held station to come home in second place with Britain's Leon Haslam (BMW Motorrad Motorsport) in third, just ahead of Melandri.

Race two boiled down to a thrilling fight between Yamaha team-mates Laverty and Melandri, but not before a dramatic moment when leader Biaggi was penalised for cutting a chicane.

The veteran Italian was comfortably leading by five seconds when he made the error midway through the 18-lap race, which triggered a ride-through penalty that in turn set up a grandstand finish between the squabbling Yamahas.

Laverty's charge back into contention had been particularly impressive after his entanglement in a multi-bike accident on the opening lap - triggered by championship leader Checa - dropped him to ninth place.

But the 24-year-old mounted a thrilling comeback ride to latch onto the tail of Melandri in the closing stages, and his recovery was completed in thrilling fashion in the final corner as he passed the sister Yamaha to claim a victory to eclipse his first.

Third place went to Michel Fabrizio (Suzuki Alstare), who got the better of former factory Ducati team-mate Noriyuki Haga (Pata Aprilia) after a race-long duel.