'It cost me': Mostert seething after costly electrical gremlin

Walkinshaw Andretti United's year of mechanical niggles has reared it's ugly head at the worst possible time, with Chaz Mostert failing to progress to the Boost Mobile Top Ten Shootout following a compromised qualifying session.

Mostert, who clawed back seven points in a truncated Friday sprint race yesterday, found himself on the back foot in both segments of Boost Mobile Qualifying this morning, one of which was self-inflicted, and the other not.

In the opening segment of qualifying, Mostert picked up kerb strikes on both of his laps in his opening run, leaving him to put it all on the line in a final run.

He secured safe passage through to Q2, but risked being buried in last on the grid if he was unable to set a lap.

However, after the brief interval, the #25 Mobil 1 Optus Mustang wouldn't re-fire, with the jump battery being brought in to fire up the engine.

Despite the car firing up, it wasn't allowed on track until the car fired up under it's own power, which saw the engine temperature raise markedly.

The team elected not to risk engine damage, putting an array of blowers through the front grille to cool the temperatures, before giving the two-time Bathurst winner one run to secure a Shootout berth.

Emotions overflowed when Mostert crossed the line, with the 33-year-old venting his frustrations. Upon returning to the garage, Mostert revealed just how costly losing the first run was.

"It cost me a run to build into it and put it all on the line," Mostert said on the broadcast.

"It costs you everything."

When asked how crucial his first run would've been in building confidence to push harder on the second run, Mostert's response was curt, but told the story: "Yep. I got nothing else to say."

Saturday's action continues with the Boost Mobile Top Ten Shootout at 12:35pm local/1:05pm AEDT, before the 78-lap Race 33 at 3:20pm local/3:50pm AEDT.