Portadown driver Colin Turkington dropped to fourth place in the British Touring Car championship after failing to secure a podium spot at Silverstone.
The BMW driver took fourth in the day's first race, fifth in the second and crashed out after leading the last.
Andrew Jordan leads the series on 378 points, followed by Matt Neal on 344, Gordon Shedden with 343, Turkington on 330 and Jason Plato on 329.
The final round of races will take place at Brands Hatch on 13 October.
Plato won the first two of Sunday's races at Silverstone while reigning champion Shedden took victory in the third.