Derby's Jon Kirkham extended his Championship lead as the ninth round of the Henderson Yamaha R1 Cup suffered two red flag incidents at Cadwell Park.

Kirkham muscled through from his seventh pole position to claim the holeshot ahead of the determined Ben Wilson and Sam Warren at the start of the 12 lap race. As Kirkham looked to extend his lead over Wilson, Gary Mason capitalised with superior drive out of Charlies to claim third from Sam Warren. Edging a clear section of tarmac behind him, Mason settled into a rhythm while Warren continued to hold off the constant pressure from Adrian Coates, Connor Cummins and Dan Hegarty.

With his lead up to almost three seconds, Kirkham was left with it all to do again as a Yaron Salinger spill at the Chicane saw first the safety car, then the red flag deployed on lap four. The re-start would see proceedings settled over eight laps with grid positions determined as of the culmination of lap two.

Kirkham lined up on pole once again onboard the blue liveried Metzeler Championship leading R1, with Wilson and Mason rounding out the front row. Wilson made a hard-fought start from the lights stick for the holeshot into Coppice, but could not prevent Kirkham moving round for the lead mid-way through Chris Curve on the opening lap.

Sam Warren made a better start to the re-start, holding third until Gary Mason drafted past along the fast Park Straight on lap 5 Adrian Coates, Dan Hegarty and Connor Cummins battled throughout the race, jockeying for position into the chicane. Coates ran deep allowing Co-ordit Racing's Hegarty through for fifth. As the front runners rounded Barn for the start of lap six, a Stuart Wilson crash at the Chicane brought the red flag out for the second time, offering Jon Kirkham his sixth victory of the year.

Darren Bellworthy, the newly crowned Derby Phoenix Club champion, made an instant impression on the series. The club racer finished in 8th ahead of a host of R1 Cup regulars, gaining 8 points. Bellworthy was joined by nine other new riders including two Hungarian riders, bringing an added international flavor to the series.

Although Jon Kirkham extends his overall lead in the series, Ben Wilson retains top slot in the Autumn Cup. The tenth round of the Championship moves to Croft Circuit in North Yorkshire in three weeks time (12-14 September).

Jon Kirkham: "Ben is just awesome on his starts, I don't know how he does it! I managed to get past him on the re-start and get away again. I'm chuffed after my disappointment at Knockhill where I made a schoolboy error in the wet. I've got a good chance of picking up the Autumn Cup now but I still remain committed to the overall championship which looks good."

Ben Wilson: "Jon has been on the pipe all weekend, he's just on form at the moment. I've just got to try and keep winning and keep the focus on the Championship. I'm leading the Autumn Cup and I'm still in the running for the main Championship."

Gary Mason: "Adrian Coates helped me there cos he ran wide and I managed to get my head down and kept pushing. It helped having a re-start as it gives me more time on the R1, jumping off the Superbike onto the R1 and back on the Superbike is hard work but I'm really enjoying my racing."