The ART duo of Lucas di Grassi (left) and Sebastien Buemi set pulses raising in the pitlane by claiming the top two positions in this morning's free practice in the closing minutes of the session in Monaco.

The iSport duo of Timo Glock and Andi Zuber got out of their cars with five minutes remaining after setting the then top two times, but two minutes later series debutant Buemi claimed the top spot, just before teammate di Grassi pipped him by less that a tenth with a time of 1:21.573.

In an eventful session Xandi Negrao literally started with a bang, running too fast through the swimming pool complex and finding the wall on his first lap out of the pits.

While Glock was already setting early fastest laps Ho-Pin Tung was also in the wars: his line into Rascasse was too sharp and, although he kept his car off the wall, a stall meant that he was also out of the session.

Bruno Senna was trapped behind him on track, but some quick thinking by the Brazilian meant that he kept his engine idling until he could get a push backwards to get by the immobile Chinese driver.

Once the track was clear the times started tumbling, with Pastor Maldonado, Andy Soucek, and Karun Chandhok all putting in competitive times to Glock and di Grassi, while Buemi looked as though he'd been in the series for years as he sliced his way around the tight track.

A quick tyre change and a clear track gave the iSport pair exactly what they were looking for: Glock put in a lap 1.2 seconds faster than the previous best of the day, and when everyone else came back out of the pits it looked as though no one would be able to better their efforts.

But the ART duo knew better and squeezed by at the top of the timesheets, with Glock finishing third fastest and just two tenths off di Grassi's best time. Behind him were Maldonado, Luca Filippi, Andi Zuber, Antonio Pizzonia, Nicolas Lapierre and Javier Villa.

With just an hour between free practice and qualifying there will be little time to find any last minute tweaks ahead of the vital qualifying session.

Provided by the GP2 Series Media Service