Having courted some controversy of his own with a robust pass on Noriyuki Haga at turn one on lap two – prompting the normally placid Japanese rider to kick out in anger as he went down the escape road -, Leon Camier soon made it an Aprilia 1-2 as he relieved Corser of second.
However, Aprilia's dream result on home soil was scuppered on lap eight when Camier low-sided out of the second Lesmo and into retirement, promoting Melandri to second, a charging Michel Fabrizio to third and Haga in fourth, while Biaggi's lead grew once more.
Laverty, meanwhile, was having an eventual afternoon, running off on lap five whilst trying to pass Haga, leaving him back in eighth again. Nonetheless, he quickly worked his way up the order to hold down third by lap eleven, behind Melandri, as the second-half of the race got underway.
Third duly became second when Biaggi peeled in, prompting an intense fight for victory with his team-mate, who was also looking for his second victory of the season.
Taking a more cautious approach in tackling his fellow Yamaha rider, Laverty stayed in the shadows of Melandri throughout the duration of the final laps, rarely showing more than a wheel as the small gap between the pair remained static down the straights.
Indeed, Melandri looked to be on course for victory as he rebuffed Laverty's determined last lap efforts, only for him to get crossed up with his troublesome gears into the final corner and running slightly wide.
It was the invitation Laverty needed to dive beneath Melandri and hold him off on the run to the finish line to claim a breathtaking second win of the day - in very different circumstances to that of his first victory.
Melandri cut a disappointed figure in second, though his strong points' haul lifts him back up to second in the standings, 27 points behind Checa.
The battle for the final podium position was arguably just as heart-stopping, with former team-mates Fabrizio and Haga going handlebar-to-handlebar at several points on the circuit as they disputed third place.
Sending Haga down the escape road, not for the first time today, at one point, the Japanese rider was relentless in his fight backs, but Fabrizio aggressively defended his position to hold onto third place by a mere tenth, the Italian scoring his first podium result for Suzuki as a result. Despite missing out on the podium, fourth is Haga's best finish yet on the PATA Aprilia.