With Checa's lap times stabilising and Sykes's beginning to dwindle, the Althea Ducati was able to make remarkably fast inroads into the British rider's lead, taking just four laps to catch and pass Sykes.
Proceeding to pull away over the remaining six laps, Checa crossed the line with a winning margin of almost two seconds to complete a third win in four races, as well as secure a popular success for Ducati on home soil.
Despite slipping into the clutches of Haslam once Checa was through, Sykes was able to hold on for a third consecutive podium finish, a result that means he has accumulated almost half of his entire 2011 points' tally in just two race weekends.
Mirroring the results sheet of the opening race, Haslam claimed BMW's first-ever WSBK double podium in third place, the Briton moving ahead of team-mate Marco Melandri in the overall standings to fourth, while Biaggi followed up just behind in what was a fairly anonymous weekend for the erstwhile series leader
Further back, an entertaining battle for fifth raged throughout the race and was eventually determined by those that made fewest errors. Indeed, Melandri, Sylvain Guintoli and Joan Lascorz all looked in contention for the position before making mistakes that dropped them back, while Davide Giugliano looked on course for an excellent top five finish before his Althea Ducati cried enough on the penultimate lap.
In the end, Honda's Jonathan Rea would prevail, despite a dramatic high-speed trip across the gravel trap at Villeneuve in the closing stages when he tagged the back of Eugene Laverty's Aprilia. Nonetheless, the Ulsterman fought back and was rewarded with a fine finish given the extent of his mammoth accident in qualifying a day earlier.
Laverty came home a fairly quiet sixth, the Irishman no doubt concerned to have finished well behind team-mate Biaggi in both races.
Jakub Smrz crossed the line seventh on what was an otherwise disappointing race day for the Effenbert Liberty Ducati team, ahead of Leon Camier, who hauled himself up to eighth place on the Crescent Fixi Suzuki for his and the team's first top ten finish of the season.
Lascorz, Melandri and Guintoli paid for their errors to finish down in ninth, tenth and eleventh respectively, ahead of Maxime Berger and Lorenzo Zanetti.
Despite an early off, Chaz Davies has broken his WSBK's points' duck with a run to 14th place, while Ayrton Badovini snatched the 15th and final point for BMW Italia.