The Walkinshaw Andretti United driver officially leads the Repco Supercars Championship after being classified second in both races at the Thrifty Newcastle 500, although Triple Eight Race Engineering's outstanding appeal could yet change that.
It was Triple Eight's Shane van Gisbergen who denied Mostert a win on the track in Race 2 at the Newcastle East Street Circuit, running down Car #25 and making the pass with less than five laps to go.
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The three-time champion had resumed his final stint nine seconds in arrears, but needed only 15 laps to overcome that deficit.
“My car just really lacks the early throttle pick-up and that's where I hurt the tyre a lot.
“I'm good for 20 laps; last 10 laps after that, it's a bit of a battle. So, once it starts to really hurt the tyre then the braking starts to struggle and stuff like.
“So, we've definitely got some work to do.
“I felt like [in Race 1] we had okay tyre life but it was similar settings for a race car and we struggled a bit more, but obviously had a bit more cleaner track [in Race 2], was pushing a bit harder, and those bigger cliffs were coming.
“We've got some good data, we'll go through it, but it's part of the challenge. It's enjoyable.
“When you're working with your engineer and you're putting bolts in different holes, it's back to old school.
“You don't have simulation or anything like that. It's go out and give the best feedback you can and hopefully you see something on the data, so it's a bit of a beast.”
While van Gisbergen had the advantage of taking his latter pit stop 12 laps later, he had, of course, only earned that advantage through careful management of his rubber in his first two stints, a point noted by Mostert.
By the time Car #97 had caught #25, a pass seemed inevitable, although it did transpire with contact in the braking zone at Turn 9 when the WAU pilot moved across to try and take the race line for the corner.
He admitted to “red mist” when he returned serve with a nudge at the next braking zone, two corners later, but admitted that the contest was over by then.
“How he drove that race, and being able to make those tyres live on that car in the second stint, getting the times from what he was doing still in that car was super-impressive,” said Mostert of SVG.
“I left it all out there, tried my hardest to make mine live, but the last 10 laps in each stint, I would just hit a cliff in deg.
“So, tried my hardest to hang on, I didn't see if Shane had overlap at that point or not, but I was just trying to get as much momentum as I can.
“Obviously there was the smallest amount and we touched and I ran wide, and then I just a little bit of red mist.
“I let him know down at the hairpin that I could bump too but I was never going to get him back; he had plenty more tyre than what I did.”