Romain Grosjean cut Giorgio Pantano's GP2 championship lead to five points with victory in race two in Istanbul while Bruno Senna hit a dog that had strayed on to the track and was forced to retire.

Britons Mike Conway and Ben Hanley collected their first points of season with fifth and sixth respectively.

Grosjean claimed his first win of the season after pressuring early leader Vitaly Petrov all through the first half of the race, taking the lead and walking away in the latter stages for a dominant victory ahead of Petrov and Sébastien Buemi.

While the French driver celebrated on the podium the sympathy of everyone in the pitlane was with Senna, nephew of three-times Formula One champion Ayrton, who drove incredibly to move up from fifteenth on the grid only to see a certain points finish destroyed when he struck the stray dog.

The incident broke his right front suspension and forced him out from sixth place.

At the start Petrov made a storming start from fourth to claim the top spot into the first turn, while Grosjean slightly pushed Karun Chandhok into polesitter Adam Carroll, allowing Buemi and Javier Villa to line up behind the Russian driver but ahead of the Frenchman as they tore up the hill.

Behind them mayhem ensued, with eight drivers out on the spot and the safety car immediately called.

At the restart Grosjean wasted no time in getting by Villa, who was also passed by team-mate Pantano a few corners later. The order was shaking out all through the field as the drivers made up for the lack of overtaking yesterday by attacking all over the circuit, although Chandhok and Villa took it a little too far and an inevitable contact put the pair into spins which would delete any chance they had of scoring in the race.

Senna, in particular, looked unstoppable as he set a string of fastest laps to move up into the points-paying positions. The Brazilian struck the dog coming into the final complex: he limped back to the pits before storming away, clearly fuming.

Just one lap later Grosjean's race-long pressure finally paid dividends as he slid inside Petrov at the end of the back straight to claim a lead which he would never look like relinquishing.

When another dog ran on track the safety car had to be brought back out, compacting the field for the final run to the flag, but Grosjean was imperious at the restart and just disappeared, while Petrov's mirrors were full of Buemi's Arden for the remainder of the race.

While the order further back was still swapping lap after lap, up front the top three were followed across the line by Pantano, Conway and Hanley, the two Britons rewarded for staying out of trouble and keeping their heads while those around them were losing theirs.

Pantano's fourth place was enough to maintain his lead in the championship over the whole weekend with 24, with Grosjean moving up to second with 19 points ahead of Buemi on 14 and Andreas Zuber with 13 points, setting up an intriguing battle in Monaco.

Racing Engineering leads the teams' championship ahead of ART Grand Prix, Trust Team Arden and iSport International.

From Official Website