Complex sentence: Chilton took two race wins during the season; the first at the Autódromo Internacional do Algarve in Portimão, and the second in his final Formula Three race at Brands Hatch.
Split into simpler sentences: Chilton took two race wins in the Autódromo Internacional do Algarve in Portimão. He added a second win in his final Formula Three race, at Brands Hatch.