Luke Browning wins dramatic GB3 race at Oulton Park ahead of Bart Horsten and Christian Mansell

Luke Browning has won the dramatic second GB3 outing at Oulton Park ahead of Aussies Bart Horsten and Christian Mansell.

Rookie Luke Browning has won his first GB3 victory on countback at Oulton Park. (Jakob Ebrey)

Championship leader Zak O'Sullivan started on pole, but Browning made his way into the lead on lap one and didn't look back in the early stages as the two leaders pulled away from the chasing pack.

Roberto Faria ran third, followed by Horsten and Mansell, and the championship looked all but over as O'Sullivan was certain to gain an unassailable points lead over second-placed Mansell.

The entire championship turned on its head on lap 10, when Browning and O'Sullivan collided, with the championship leader retiring as he came to rest in the barriers.

Browning came into contact with Faria just two laps later, as the chasing Australian duo narrowly avoided turning the clash into a multi-car pile-up.

Horsten inherited the lead, with Mansell in second, but the race was red flagged, with Browning claiming the victory on countback after initial confusion.

The win was Browning's first, having only entered the GB3 championship this weekend.

O'Sullivan maintains a dominant championship lead with one race remaining this weekend before the series finale at Donington Park.