Reynolds’ time in the #20 Team 18 Chevrolet Camaro, a 1:19.5831s, was set on his fourth lap of the Adelaide Parklands Circuit.

However, Waters beat it by just 0.0067s at the death with a 1:19.5764s in the #6 Tickford Racing Ford Mustang.

Six drivers elected to put a second set of new soft tyres in the 30-minute session – including Waters, Brodie Kostecki, Thomas Randle, Will Davison, Cooper Murray, and Jaxon Evans.

“We were pretty happy,” said Waters.

“The car rolled out pretty good, we tried to learn some stuff, put a tyre on at the end and got a bit of traffic.

“But the car is pretty pacey, so a good start.”

Kostecki was third-best in the #38 Dick Johnson Racing Mustang. He was the only driver to graze the Turn 8 wall, stripping some of the paint from the left side of his car.

Team 18 continued its rich run of speed with Anton De Pasquale fourth fastest in the #18 Camaro ahead of fifth-placed Thomas Randle in the #55 Tickford Mustang.

Chaz Mostert was the best of the championship contenders in sixth, climbing up the order in the final few minutes of the half-hour session.

Just behind the #25 Walkinshaw Andretti United Mustang was Will Brown in his #1 Triple Eight Race Engineering Camaro, a mere 0.0172s adrift.

Brown’s teammate Broc Feeney was 11th in the #88 Camaro, 0.5731s off the pace. Feeney was captured having a moment at Turn 7, cranking his car sideways over the top of the kerb and aborting his flying lap.

There was a scary moment for Kai Allen in the closing minutes when he had to check up approaching Turn 1 as Andre Heimgartner came out of the pit lane. Allen ended the session 18th fastest and eight tenths off the pace.

NASCAR star Austin Cindric was 23rd with a 1:20.7125s in the #5 Tickford Mustang to be 1.1361s off the quickest time.

Practice 2 at the BP Adelaide Grand Final takes place on Friday at 10:30am ACDT.

Results: Repco Supercars Championship BP Adelaide Grand Final, Practice 1