Pole-sitter Raffaele Marciello held the lead through a lively opening hour of the Total 24 Hours of Spa which got underway in dry but overcast conditions.
The AKKA-ASP Mercedes-AMG GT3 Evo driver led fellow Italian Mattia Drudi by 5.5 seconds coming to the end of the first stint after Drudi made up two positions from his fourth-place grid start in the No. 66 Audi Sport Team Attempto entry.
No positional changes occurred in the top six during the opening half-hour, which included an early Safety Car for the retrieval of tire debris from a puncture.
Several cars encountered punctures in hour one, including KCMG’s No. 21 Porsche 911 GT3 R, Attetmpto Racing’s No. 55 Silver Cup Audi and the Pro-Am Rinaldi Racing Ferrari.
There was also an accident for the Pro-Am Orange 1 FFF Racing Team Lamborghini Huracan GT3 Evo of Hiroshi Hamaguchi who impacted the left-side barriers after spinning at the exit of Turn 9. Hamaguchi managed to return to the pits but with car damage
The top-six picture then changed after 35 minutes, approximately 13 minutes on from the restart, when Drudi profited from Audi Sport Team WRT’s Christopher Mies sliding wide upon entry to Pouhon.
Mies’ mishap enabled third-placed Maro Engel in the No. 4 Haupt Racing Team Mercedes-AMG GT3 Evo and Drudi to get right on the tail of the WRT car through the next sequence of corners.
Drudi slotted his Audi in front of Engel’s Mercedes-AMG in the esses to take third before blasting into second past Mies on the run down to Blanchimont.
This battling enabled Marciello, who shares the AKKA-ASP car with Felipe Fraga and Timur Boguslavskiy, to open up a lead of almost five seconds.
Engel briefly got past Mies into Bus Stop before the HRT man lost ground at the start of the next lap, falling into the clutches of the group of cars behind.
Engel then quickly composed himself to regain fourth behind the factory-supported Audis of Drudi and Mies, and ahead of Porsche 911 GT3 R drivers Thomas Preining of GPX Racing and Michael Christensen of KCMG.
Dennis Lind was seventh for Orange 1 FFF Racing Team and Markus Winkelhock eighth for Audi Sport Team Sainteloc.
The No. 78 Barwell Motorsport Lamborghini led the first hour of the Silver Cup contest after progressing to the front from fifth on the class grid.
Frederik Schandorff had just over a second in hand to Aurelien Panis in the Tech 1 Racing Lexus RC F GT3, with Hubert Haupt in third for his eponymous Mercedes-AMG team.
In Pro-Am, Maxime Martin put Garage 59’s No. 188 Aston Martin Vantage GT3 into the lead with an overtake on pole-sitter Robert Renauer in the No. 991 Herberth Motorsport Porsche.
Am Cup was led by Stefano Constantini in the Raton Racing Lamborghini which started from pole.