Northern Ireland pair Alastair Seeley and Andy Reid secured victories in the latest BSB round at Oulton Park.
Carrickfergus rider Seeley edged out Fermanagh man and series leaders Josh Elliott to win a thrilling Superstock 1000c race.
Reid clinched his maiden Supersport win in the sprint race with Glenn Irwin fourth in Sunday's feature event.
Toomebridge's Michael Laverty could only manage a best finish of seventh in the three Superbike races.
The Tyco BMW rider came in ninth and 12th in the other two races in England and lies sixth in the championship.
Laverty will compete in the end-of-season showdown involving the top six in the series.
Seeley cut Elliott's lead at the top of the Superstock 1000c standings to 17 points after winning by just 0.121 seconds.