James Courtney has set the pace in an opening full-field practice session for the OTR SuperSprint The Bend which was twice disrupted by red flags.

In the second session for Supercars on the South Australian venue’s West Circuit layout, the Tickford Racing driver set a 1:15.4821s just after what should have been a 30-minute hit-out restarted for the first time.

That lap was still the fastest when a second red flag brought a slightly premature end to proceedings, leaving the #44 Boost Mobile Mustang on top by 0.0384s over championship leading Scott McLaughlin (#17 Shell V-Power Mustang).

Red Bull Holden Racing Team duo Shane van Gisbergen (#97 ZB Commodore) and Jamie Whincup (#88 ZB Commodore) ended up third and fourth respectively, ahead of the entry which caused the second stoppage, namely the #2 Mobil 1 Middy’s ZB Commodore of Bryce Fullwood.

Chaz Mostert (#25 Mobil 1 Appliances Online ZB Commodore) was fastest early on with only around half the field having set anything resembling a representative lap time when Anton De Pasquale drew a red flag.

The Erebus Motorsport driver had stopped on track but was able to get the #99 Penrite ZB Commodore back to the pits at slow speed, after which he suggested that an electrical issue was to blame.

Mostert’s initial 1:16.5438s was bettered almost as soon as the field was let loose again following a brief delay in proceedings, first by Andre Heimgartner’s 1:16.2741s in the #7 Ned Mustang.

Once most had completed one lap after the restart, Courtney was top with that 1:15.4821s, 0.2527s faster than Whincup and 0.6122s up on McLaughlin.

The latter’s position fluctuated within the top 10 before he moved to second spot with a 1:15.5205s on his third run.

Van Gisbergen jumped to third position in the minutes before the second red flag with a 1:15.6725s, pushing Whincup back to fourth and Fullwood to fifth.

As De Pasquale had done, Fullwood brought a halt to proceedings due to stopping on the race track, before completing a power cycle and driving back to pit lane.

“(I’m) Not too sure what really happened there, to be honest,” said the Walkinshaw Andretti United driver shortly after the session.

“I was starting a lap there, I was just warming up, and then it just died on me. The motor was running really rough, then ( just did a power cycle and it all came good again, so I’m not really too sure what happened.”

With only 1:42s left on the clock after that drama, officials opted to not restart the session again.

That locked Lee Holdsworth (#5 Truck Assist Mustang) into sixth and Nick Percat (#8 R&J Batteries ZB Commodore), who had not long spun at Turn 1, into seventh.

Rounding out the top 10 were Heimgartner, Jack Le Brocq (#55 Supercheap Auto Mustang), and De Pasquale, who was reportedly sent back out with a new ECU and battery.

Mostert ended up 16th at 0.7689s back from Courtney and while Fabian Coulthard finished 20th-fastest in the #12 Shell V-Power Mustang at 0.8027s off the pace.

Practice 2 for the Virgin Australia Supercars Championship field starts at 11:00 local time/11:30 AEST.

Results: Practice 1