The Walkinshaw Andretti United driver took the chequered flag in first position in the Bosch Power Tools Perth SuperSprint finale by a margin of 2.4115s over Cam Waters.

Unfortunately for Mostert, he had a five-second penalty hanging over his head and hence the #25 Mobil 1 Optus Mustang was officially classified second at 2.5885s behind his former team-mate.

“Yeah, that sucks,” admitted the Race 9 winner after Race 10 at Wanneroo.

“I didn’t expect us to be really close with anybody else so we’ll have to go back and understand.

“But, you know, you’ve got to lay it all on the line and I sent it out, I probably got a little bit hesitant, the radio call was “Merge, merge, merge,” but I swear I was clear just from my perception but I hesitated a little bit and then I still committed to it.

“So, yeah, a little mistake on my part there, so I’ll take that one and no doubt we’ll regroup, come back.

“But overall, super-fast car, it’s nice to just have pace and be able to feel like you can win.

“A win yesterday, I feel robbed, I would have loved to have won today, but it wasn’t meant to be.

“I’ll take the fastest lap and P2 in that one and still crossed the line first, so I’ll still put it in my win tally anyway.”

Mostert had pitted from a 1.6s lead over Waters on Lap 28 and was followed into the lane by the other Tickford Racing entry, the #55 Mustang of Thomas Randle.

WAU changed four tyres on Car #25 and Tickford only sides on #55, hence they arrived at the same piece of real estate in the fast lane.

Mostert’s car controller had been heard on the radio saying, “Behind this car, behind this car,” then when it looked like #25 might be clear, added, “Okay, go, go, go… Oh sorry mate,” as Randle lifted the throttle and dabbed the brakes.

Mostert assumed the lead again when the pit stop cycle wrapped up and stretched it to almost the magic five-second mark with about 15 laps to go.

Waters, who did take four tyres and hence had been allowed an easy overtake for second place by Randle, then began to turn the tide and take the race away from #25.

Asked if he thought he had enough to cover the five second, Mostert replied, “I didn’t really race the race I wanted to race, to be honest.

“Obviously, we got called in a little bit earlier than Cam. So, that last stint, I probably would have gone out a little bit softer, probably burnt the tyres up a fair bit trying to gain that five-second gap after we had the penalty.

“So, definitely didn’t have the strong car at the end like I would normally have, but I didn’t everything I could to try and make up the deficit.

“But, unfortunately Cam just kind of eased into it. He knew I had the penalty, he played a smart race to get inside that gap, but yeah, just couldn’t hold that five seconds.”

Mostert has now closed to 39 points behind second-placed Broc Feeney in the drivers’ championship.