Mostert merged into the path of Thomas Randle after their compulsory pit stops and would be pinged five seconds for the breach.

The #25 Mobil 1 Optus Mustang resumed the lead when the pit cycle shook out but took the chequered flag only 2.4115s up on the #6 Monster Energy of Mustang and hence dropped to second in the official classification.

Will Brown also copped a five-second penalty, for pushing Randle off the road, but beat Will Davison to third place by six seconds and thus the #87 Red Bull Ampol Camaro still officially finishes on the podium.

The win is Waters’ and Tickford’s first of the year, while Mostert scored the fastest lap bonus points and Brown extended his championship lead over team-mate Broc Feeney to 136 points.

Waters had qualified on pole position and led the field into the first corner, with Mostert second and Randle (#55 Castrol Mustang) moving across from the outside of Row 2 into third, ahead of Brown, Brodie Kostecki (#1 Erebus Motorsport Camaro), Davison (#17 Shell V-Power Mustang), Anton De Pasquale (#11 Shell V-Power Mustang), and Ryan Wood (#2 Mobil 1 Truck Assist Mustang).

Waters lost the lead before the standing lap was done when he skated wide at Turn 7, possibly due to the presence of dirt left on the track from a Super2 race, and opened the door for Mostert.

About five laps in, Feeney reported a vibration in the #88 Red Bull Ampol Camaro, by which time he had risen from a relatively lowly 12th on the grid to ninth.

He gained another position when he squeezed down the inside of Wood at Turn 7 on Lap 10, as Mostert circulated just over a second clear of Waters at the front of the field.

Matt Payne (#19 Penrite Mustang) started 16th but was 10th when he overtook David Reynolds (#20 Tradie Beer Camaro) on Lap 15, before Wood became first of the top 10 to pit when he took working side tyres on Lap 19.

A lap later, Kostecki was in from fifth, but straight into the garage and the bonnet went up on Car #1.

Mostert was about 1.6s up on Waters when he pitted on Lap 28 and was followed into the lane by Randle in a pivotal moment in the race.

Tickford changed sides on #55 but WAU went for all four corners on #25 and Mostert was initially told to merge behind, only he went in front and forced Randle to lift and touch the brakes.

Waters pitted for four tyres on Lap 30, Brown likewise on Lap 31 as De Pasquale took green sides, Davison on Lap 32 for green sides, and Feeney on Lap 33 for four tyres.

As that was going on, Race Control announced a five-second penalty against Mostert for an unsafe release.

When Nick Percat (#10 Bendix Camaro) stopped on Lap 35, the cycle was done and Mostert led again, but only by about 2.6s over Randle.

Waters was third, from Wood and Brown, who had not long passed Davison at Turn 7, with De Pasquale seventh, from Payne, Reynolds, Richie Stanaway (#26 Penrite Mustang), and Feeney in 11th.

Brown passed Wood for fourth into Turn 7 on Lap 37 and Randle stepped aside on Lap 38 at Kolb Corner to let Waters, with his four fresh tyres, give chase to Mostert.

The Saturday race winner had stretched his lead to almost five seconds around the time that the Tickford team-mates reordered themselves, but Waters had brought it down to less than three seconds with five laps to go.

Meanwhile, Brown had caught Randle, who went very defensive into Kolb on Lap 49.

At the other end of the back straight, they made nose-to-tail contact which resulted in Randle being pushed off the track and dropping back to fifth, between the Dick Johnson Racing Mustangs.

The matter was referred to stewards and a five-second penalty was handed down, but Brown was running about six seconds ahead of Davison at the time and hence would hold position if it remained that way.

Waters continued to chip away at Mostert’s lead in the final laps and Brown kept his head above water in the virtual battle for third place with Davison.

Randle ended up fifth, from De Pasquale, with Feeney climbing to seventh at the finish, from Wood, Payne, and Reynolds in 10th.

Stanaway got home in 12th and Andre Heimgartner (#8 R&J Batteries Camaro) in 15th, with Kostecki the only DNF.

A number of teams are set to test later this month before Event 5 of the season, the betr Darwin Triple Crown at Hidden Valley Raceway on June 14-16.

Results: Race 10, Bosch Power Tools Perth SuperSprint

Fastest lap (bonus): Chaz Mostert, 0:55.6345s, Lap 30

Drivers’ championship

Teams’ championship