Huber Motorsport driver Cairoli topped the times in Friday afternoon’s Superpole session for the fastest 20 cars in the opening qualifying session on Thursday.
The Italian posted a 2m16.880s on his first flying lap aboard the #20 Porsche 911 GT3-R to edge out AF Corse Ferrari driver Alessio Rovera by just over a tenth.
Cairoli and team-mates Jannes Fittje, Tim Heinemann and Antares Au are competing in the Bronze Cup class, which means the Huber Porsche is the first car from outside the Pro category to take the pole at Spa for 10 years.
The Huber Porsche made it through into the Superpole after rain hit during the aggregate qualifying session on Thursday evening.
Only the first of the four mini-sessions was dry, which counted against the three-driver Pro line-ups that didn’t take to the track until after it had started raining.
Just seven of the 20 cars entered in Pro made it through to Superpole as a result.
“It was quite unexpected,” said Cairoli after the session. “It was an 80% lap: I made some mistakes, but I’m happy to be on pole.”
Rovera was the top Pro entry in Superpole aboard his Ferrari 296 GT3 with a 2m16.996s.
Klaus Bachler made it two Bronze Cup Porsches in the top three aboard his Herberth-run Pure Racing entry.
He posted a 2m17.232s on his first flying lap before aborting his second after a trip through the gravel.
Franck Perera took fourth and second in the Pro category aboard the K-Pax Lamborghini Huracan EVO2 with a 2m172.43s.
Fifth quickest was Dean Macdonald in Optimum Motorsport’s Gold Cup class McLaren 720S GT3 just six hundredths behind with a best lap of 2m17.249s.
The top six was rounded out by Ricardo Feller, who posted a 2m17.293s in the Tresor Attempto Audi R8 LMS GT3 EVO II.
Fabrizio Crestani was fastest in the Silver Cup class with a 2m17.365s that put him seventh aboard his Grasser Racing Team Lambo.
The top Mercedes-AMG GT3 was the GruppeM entry in which Maro Engel took 16th position.
No BMWs made it through to Superpole, the two factory-backed WRT entries just missing out in 21st and 22nd position.
The Spa 24 Hours, round three of the Endurance Cup segment of the GTWCE Europe, starts at 16:30 local time on Saturday.