The British Touring Car title duellists Fabrizio Giovanardi and Jason Plato finished first and second in the first race at Thruxton.
The first of the three races that will decide the title was hit by a spate of tyre failures that affected most of the title contenders’ team mates.
It leaves Plato six points ahead of Giovanardi with two races remaining.
The Vauxhalls ran 1-2-3 for most of the race with pole sitter Tom Chilton giving way to Giovanardi on the third lap.
Plato fell back from fourth at the start but took the position back at the first corner, passing Matt Neal.
That left Plato fending off Colin Turkington, who had edged past Neal for fifth. Neal now had Darren Turner looking for a way past and the Yorkshireman squeezed through on the second tour.
Turner then took fifth off Turkington on the seventh lap, taking up position behind team mate Plato.
Having dropped back in the early laps Plato now closed to within half a second of Alain Menu, the Swiss appearing for Vauxhall as a one-off in the final race.
It all looked set for a Vauxhall formation finish until, with three laps to go, Chilton speared off the track at Church with a deflated front-left tyre.
When Matt Allison began crawling with an identical problem it became clear all the teams were struggling with tyre wear – but would any more of the leaders be hit?
On the next lap Turner’s Seat suddenly slowed and he headed for the pits. As the cars began the final lap Plato was right behind Menu – the Vauxhall driver was also slowing with a flat tyre and could do noting to fend off the Seat.
Even Giovanardi seemed to be in trouble – but he crossed the line a second ahead of Plato to cut the championship gap by four points.
Gordon Sheddon took third off Menu before the finishing line, the Swiss finishing fourth ahead of Neal and Turkington.
