Despite renewed opposition Ivan Bellarosa picked up two more wins as the SPEED EuroSeries visited Imola for the fifth and sixth rounds of their season and maintained his commanding lead in the chase for the Sunoco Rolex 24 at Daytona Challenge.

Italian Bellarosa had to contend with former GP2 driver Davide Rigon in a works run Tatuus chassis, as well as Line Race driver Yann Zimmer, and both were ahead of Bellarosa by the end of the opening lap of the weekend's first race, Rigon pulling away into an eleven second lead over Zimmer.

The reason for Rigon's pace – however – had been that the Tatuus team planned to exploit a loophole in the regulations. Though refuelling in the pitlane is outlawed, there was not explicit ban on refuelling in the garage, and the light Tatuus had the obvious advantage before having to pit when, through clever, the additional time in the pits proved costly.

Bellarosa also struck trouble in the pits, miscommunication in the crowded pitlane resulting in an under-length stop which incurred a hefty 32 second penalty despite which Bellarosa still finished ahead of Zimmer in third and Rigon in second.

Sunday's race was made more straight-forward by the banning of refuelling mid-race – a direct response to Tatuus' Saturday tactics – and the team withdrawing Rigon from the race.

Taking the lead from the start of the race Bellarosa consistently pulled out a lead on Zimmer thoughout the first half of the race before easing back, allowing the chasing Frenchman to finish 14 seconds adrift. The combination of Darren Burke and Duncan Williams rounded out the podium to keep fifth in the Challenge points standings while fourth place finisher at Imola Anthony Gandon lost further ground to Bellarosa in the Challenge, though he ended the weekend as the Italian's nearest challenger.

In the Britcar MSA British Endurance Championship – the only other series with drivers competing in the Sunoco Challenge for the chance to win a drive in a Daytona Prototype at the 2012 Rolex 24 at Daytona – Javier Morcillo lost more ground after a difficult race at Oulton Park.

Part of the leading group in the early stints of the three hour race Morcillo's Neil Garner Motorsport run Mosler was delayed with a broken driveshaft that could only be fixed in a long visit to the pits. The trouble limited them to just 13th overall, but second in class behind the Ferrari 430 of Andy Schulz and Paul Bailey.