The Belgian squad’s #31 factory Audi R8 LMS driven by Dries Vanthoor, Christopher Mies and Kelvin van der Linde ended up nearly two tenths clear at the head of the times in the night-time aggregate session held on wet track.
Van der Linde set the fastest time across the four 15-minute periods with a 2m34.255s, while Mies was quickest in Q3 with a 2m35.298s and Vanthoor second in Q2 with a 2m35.738s.
That gave them a 2m35.097s average, which compared with a 2m35.282s for the second-placed GPX Racing Porsche 911 GT3-R shared by Matt Campbell, Patrick Pilet and Mathieu Jaminet.
Van der Linde said: “Great turnaround by the team, because the car wasn’t great in prequalifying.
“Credit to them for giving us a car that was competitive in all three sessions.”
Campbell had been quickest in the opening session for the three-driver crews competing in the pro class with a 2m35.013s.
The #66 factory Attempto Audi driven by Mattia Drudi, Patrick Niederhauser and Frederic Vervisch took third place with a 2m36.249s average.
Factory Mercedes-AMG GT3s took fourth and fifth positions in the session.
The Auto Sport Promotion car driven by Raffaele Marciello, Timur Boguslavskiy and Felipe Fraga was less than two hundredths clear of the HRT Merc of Maro Engel, Luca Stolz and Vincent Abril.
The factory AF Corse Ferrari 488 GT3 of James Calado, Nicklas Nielsen and Alessandro Pier Guidi was sixth.
Last year’s winners Kevin Estre, Michael Christensen and Richard Lietz were 10th in their KCMG Porsche.
Top Lamborghini Huracan GT3 Evo was the FFF entry driven Dennis Lind, Marco Mapelli and Andrea Caldarelli.
The fastest 20 cars from first qualifying go forward into Friday evening’s final session that will determine the first 10 rows of the grid.
The remainder of the grid is based on the positions from Thursday’s opening session.
Bernhard forced to withdraw
Two-time Le Mans 24 Hours winner Timo Bernhard has had to withdraw from the Frikadelli Porsche line-up for Spa.
The late arrival of his COVID-19 test, mandatory for everyone attending the Spa race, meant he was unable to reach the circuit in time.
His place in the #22 Porsche 911 GT3-R alongside Frederic Makowiecki and Dennis Olsen has been taken by Jorg Bergmeister.
Watch the 2020 Spa 24 Hours live and uninterrupted on Motorsport.tv.
