With Biaggi unable to score, Melandri has moved up to second in the standings, but the 76 point deficit marks Checa's largest margin over his rivals since the season began, while the Spaniard has a further opportunity to extend his advantage in race two.
Behind Melandri, Haga flew the flag for the beleaguered Aprilia brand in third position, the Japanese rider scoring a second podium of the season for a delighted PATA Racing team. Unable to keep up with Melandri, Laverty was forced to settle for fourth place.
If the race for the win proved predictable, then the fight behind them remained anything but as an intense battle for fifth all the way down to eleventh provided continuous entertainment.
In the end, Leon Haslam prevailed, but only after an extraordinary fight back on the BMW from 14th position midway through the race. The Briton had been running a fairly lonely fifth in the opening stages, but a trip across the gravel on lap seven would see him plummet down the order.
Nonetheless, a series of impressive moves – including a last lap pass on Sylvain Guintoli – would see him regain the position at the chequered flag, no doubt delighting his local manufacturer.
Behind Guintoli, Joan Lascorz was another to launch his decisive bid on the final lap as he snatched seventh on the very final corner from Leon Camier, the Aprilia rider yo-yoing through the order as he attempted to recover from a lowly 13th on the grid.
Ayrton Badovini continued his impressive run of top ten finishes – now up to twelve in a row – in ninth after making two important passes in the final two laps, the Italian heading up Jonathan Rea, who finished his comeback race in tenth. Tom Sykes valiantly held fifth for much of the race, but would eventually be swamped as his pace dropped in the closing stages, the Kawasaki rider left a somewhat unsatisfying 11th.
Mark Aitchison scored more solid points for Pedercini Kawasaki in 12th, with James Toseland 13th in his 200th WSBK race, Roberto Rolfo in 14th and Troy Corser in 15th.