Having failed to win from pole 24 hours earlier, Bortolotti made a superb getaway when the lights went out, the championship leader scored his third win of the season, with Mike Verschuur (McGregor by Equipe Verschuur) taking second and Max Braams (Las Moras by Equipe Veschuur) third.
Kevin Gilardoni made a clean start to the race, while Bortolotti jumped up two places at the expense of Kelvin Snoeks and Erik Janis, with Verschuur holding on to P5. Then at the chicane Bortolotti outbraked his stablemate to dive into the lead.
Though pit strategies varied, the race positions stayed the same through to the closing stages, with Snoeks puncturing on lap 12 and Gilardoni suffering the same fate three laps later.
Bortolotti was untroubled up front, however, and took the flag from Janis, who was later disqualified for having less than three litres of fuel in his tank, and Verschuur.
Bortolotti said: “I’m delighted. It felt like a win to finish fourth yesterday after the problems I had, and winning today from the second row feels even better. I had my sights set on the podium but my pace was really good. It’s a great result in terms of the championship.”