AKKA-ASP held the net advantage at the Joburg Kyalami 9 Hour with three hours of the Intercontinental GT Challenge powered by Pirelli season finale left to run.
Raffaele Marciello put in a charging stint after a strong run from Timur Boguslavskiy to build a gap at the front of the field in the No. 89 Mercedes-AMG GT3 Evo, which is pitting several laps earlier than its Pro-class rivals after going off-sequence in pit stops just after the three-hour mark.
With Audi confirmed as the 2021 manufacturers’ champion following the No. 71 Ferrari entry’s retirement, the closing stages of the race at Kyalami will focus on the drivers’ title.
Boguslavskiy can feasibly secure the championship but the Russian is unlikely to do so because he needs all three of the other Pro contenders to hit trouble.
The title battle lies behind the increasing lead held by the AKKA-ASP Mercedes-AMG, with the two Audi Sport Team crews trying to overcome points leaders Alessandro Pier Guidi and Come Ledogar from AF Corse.
At the close of six hours, Pier Guidi and Ledogar’s co-driver Miguel Molina held net second aboard the No. 51 Ferrari, which sat around half a minute ahead of the third-placed No. 25 Audi R8 LMS GT3 Evo of Kelvin van der Linde.
Van der Linde’s co-drivers Markus Winkelhock and Patric Niederhauser, and net fourth Christopher Haase, need to beat the remaining Ferrari to clinch the title.
Boguslavskiy held a three-second lead over Ledogar at the halfway mark and stood approximately seven seconds clear when Marciello took over the AKKA-ASP Mercedes-AMG with four hours to go.
The Swiss driver then set multiple fastest laps on his way to ballooning the buffer over Molina to 18 seconds when he made his latest off-kilter pit stop 15 minutes before the end of the sixth hour.
Audi Sport Team Sainteloc moved ahead of Audi Sport Team WRT on five hours when Winkelhock emerged from the pits ahead of Charles Weerts.
When the race ticked into its final three hours Marciello was running fourth overall, but the three other Pro cars were due to stop imminently.
While AKKA-ASP held the outright advantage, the team’s SunEnergy1 Racing-backed Mercedes-AMG entered its pit garage after six hours with a power steering issue.