TWO of among the longest race winning streaks in Porsche Paynter Dixon Carrera Cup Australia championship history have dramatically come to an end in a typically unpredictable day of racing at Sandown Raceway.

Two dramatic races saw a pair of winners each in Equity-One Pro and SP Tools Pro-Am, with the second race of the day delivering fresh winners in both classes.

Harri Jones and Adrian Flack claimed the wins in the first sprint race of the day, before a wildly unpredictable Enduro Cup race saw their winning runs ended.

Jackson Walls ended Harri Jones' winning run at seven straight races in Pro, while Matt Belford took the Pro-Am win to end an Adrian Flack winning run that dates back to the Australian Grand Prix in March - 12 race wins ago.

The sprint race was held in fully wet conditions with Dylan O'Keeffe getting the best jump from the outside of the front row, beating Harri Jones into the first corner.

The pair then engaged in a tight duel for the lead, pulling away from the pack as they battled with intensity - both surviving several near-miss moments on an incredibly slippery circuit.

Jones would eventually pounce, grabbing the lead mid-race before pulling away from O'Keeffe. Bayley Hall spent his race fending off Fabian Coulthard before eventually claiming his first top three finish since Round 1 at the Grand Prix, with Coulthard next.

David Russell completed the top five with Walls, Morris, Dale Wood, Zac Best - on debut - and Glenn Wood completing the top 10.

In SP Tools Pro-Am, Adrian Flack won his 12th straight race, beating home a recovering Sam Shahin and Rodney Jane.

Shahin started slowly having been unable to see the repeater start lights on the grid, while Jane's podium was the seventh of his season.

The Enduro Cup race was intense before the red lights went out with a rain shower moments before the race casting doubt over whether wet tyres or dry were the best option.

Nine cars elected for slicks, while the contenders at the front of the field remained wedded to their Michelin Wets as the race commenced.

That would prove to be the winning decision as a shower mid-race removed any possible late-race advantage the slick runners would have had.

Through it all came Jackson Walls, who made a perfect start and then passed Dylan O'Keeffe to grab the lead early in the race.

He then fended off a mid-race charge from Jones to secure his second win of the season, his fourth overall and first since Taupo earlier this year.

It also saw the Objective Racing driver extend his lead in the Endurance Cup championship, having come into the round leading the Carrera Cup 'race within a race'.

Jones continued his momentum with a recovery drive to second - having slipped to third at the start - while a charging drive from David Russell late in the day saw him edge Dylan O'Keeffe to third place by less than a car length following a last corner move.

With O'Keeffe fourth, Nash Morris charged to fifth while Fabian Coulthard was sixth. Hall - who survived a wild 360-degree spin on lap one - Lockie Bloxsom - who scored his best ever Carrera Cup result - Ryder Quinn and Caleb Sumich completed the top-10.

Matt Belford won the Pro-Am fight, scoring his first win of the season in his ID Group / Melbourne Performance Centre entry.

Making the right call to start on wets, Belford jumped to the lead after early leader Dean Cook survived an off in the wet conditions.

With Flack and Shahin among those starting on slicks, Belford took full advantage and powered to victory - remarkably winning by a full lap.

Cook survived to second while Matt Slavin scored third in class.

A third and final race completes Round 5 of the championship on Sunday at the Penrite Sandown 500, with the sprint race set to start at 12:00pm - broadcast live on Fox Sports 506, Kayo and Sky NZ.