Antonio Pizzonia wins on Auto GP debut at Curitiba

While Quaife-Hobbs was delayed in the pits, Varhaug would chase Pizzonia to the flag, but could not deny the Brazilian.

Pizzonia, who is competing in this year's Brazilian Stock Car series, was drafted in by Ombra in place of the team's GP2-tied Venezuelan Giancarlo Serenelli.

Despite having made just two single-seater starts in three years, Pizzonia executed a brilliant getaway from third on the grid to lead into Turn 1.

In clean air, Pizzonia built a five-second lead in seven laps over second-placed Varhaug, as the Norwegian initially struggled to find pace running a mix of medium and soft compound Kumho tyres.

Varhaug benefited from a fast turnaround during his mandatory pitstop to bring the deficit down to just over a second at the chequered flag, but the Virtuosi UK driver never staged a threatening overtaking attempt.

"I wasn't expecting this," said Pizzonia, who brought Ombra its victory of the season. "My biggest concerns were the start and the pitstop, as I practiced both yesterday and they hadn't gone that well. My start was good, not great, but because the front row got away so badly I was able to take the lead.

"I knew I needed to build around a five-second lead in case there was a problem in the pits, and that proved correct as Pal was much closer to me at the end. But it has been a perfect weekend."

After suffering gearbox problems in a disrupted practice, Sergey Sirotkin produced a strong recovery from fifth on the grid to take third. The Russian was part of a close, three-way, scrap for second with Varhaug and polesitter Quaife-Hobbs during the opening laps.

Sirotkin opted to make his mandatory pitstop four laps later than Pizzonia, enjoying a brief spell in the lead until finally coming in at the end of lap 17. The Russian gained a position when poleman and championship leader Quaife-Hobbs suffered a protracted pitstop owing to trouble securing his right-rear wheel.

Super Nova racer Quaife-Hobbs fought back to salvage sixth place, finishing on the gearbox of fellow slow-starting front-row man Chris van der Drift, but the Briton has seen his advantage in the drivers' standings reduced from 74 to 64 points by Varhaug.

Van der Drift ran in close formation with his Manor MP Motorsport team-mate Daniel de Jong in the early laps, before appearing to struggle with oversteer and leaving de Jong to a relatively lonely run to fourth.

Results - 23 laps:

Pos  Driver               Team            Time/Gap
 1.  Antonio Pizzonia     Ombra         28m51.683s
 2.  Pal Varhaug          Virtuosi UK     + 1.142s
 3.  Sergey Sirotkin      Euronova        + 5.104s
 4.  Daniel de Jong       Manor MP       + 17.299s
 5.  Chris van der Drift  Manor MP       + 23.755s
 6.  Adrian Quaife-Hobbs  Super Nova     + 24.065s
 7.  Rafael Suzuki        Ombra          + 33.184s
 8.  Francesco Dracone    Virtuosi UK    + 55.201s
 9.  Michele la Rosa      MLR71        + 1m07.697s

Retirements:

     Max Snegirev         Campos           16 laps
     Sergio Campana       Euronova         13 laps
     Giuseppe Cipriani    Campos            0 laps