To his credit, Melandri would get the bike to the finish line, but not before he had been dumped to 12th place having run in third position during the early laps.
With Laverty, Sykes and Melandri all enduring mixed fortunes over the course of the day, it was arguably Guintoli that came away as the day's big winner, his brace of second places putting him 28 points clear at the top of the standings after six rounds.
Though chased down by Guintoli, Rea was still able to pick up a comfortable third place finish at the end of a frustrating day, the Ulsterman finishing well ahead of Loris Baz, who spared some blushes for Kawasaki by claiming a strong fourth place.
Similarly, Chaz Davies helped BMW into the top five with a late pass on Carlos Checa, the Spaniard nonetheless giving the Alstare Ducati 1199 Panigale its best WSBK finish to date.
Jules Cluzel crossed the line seventh, albeit at the expense of Fixi Crescent Suzuki team-mate Leon Camier who retired with mechanical issues, while Ayrton Badovini and David Giugliano picked up eighth and ninth.
Michel Fabrizio rounded out the top ten, the Italian – along with Max Neukirchner – adding insult to injury to an embattled Melandri by passing the BMW rider on the final lap.
Behind them, Federico Sandi beat team-mate Alexander Lundh to the finish line for 13th, with Vittorio Iannuzzo scoring the final point in 15th.