Drivers with previous experience of the GP2 Series topped the individual sessions of the opening 'winter' test at Jerez de la Frontera, with Andy Soucek topping the combined times after Adam Carroll set the morning pace.

Both drivers have enjoyed an upturn in form this season, Carroll in the middle of the campaign after returning to GP2 from the DTM and Soucek in the final couple of rounds after DPR finally found some answers for its previously recalcitrant Dallara.

The Spaniard proved his recent run of podiums was no fluke with the best time of the afternoon session at Jerez. Remaining with DPR, Soucek set his time, a 1min 28.059secs effort, towards the end of the three-hour session, despite a number of red flags and the best efforts of the ART duo of Mike Conway and Sebastien Buemi, who wound up second and third fastest.

The session had appeared calm until the final hour but, with drivers switching outfits for day two on Friday, the final 45 minutes resembled a qualifying session as everyone tried to leave a lasting impression. The red flag came out five times in that final foray, however, with Adam Kahn, Michael Herck, Andi Zuber, Roldan Rodriguez and Marco Bonanomi being the guilty parties.

It was Bonanomi who finished the afternoon as the top non-2007 GP2 Series driver, taking fourth position in the Minardi Piquet Sports car - by two-thousandths of a second from Racing Engineering's Javier Villa. Bruno Senna took his Campos car into sixth position, with morning pacesetter Carroll seventh for iSport International. Eighth place went to Rodriguez in the second Minardi, with Zuber ninth for Trident. Luca Filippi book-ended the top ten in the second DPR car as he helped lend his experience to the British team.

As expected, the opening day of post-season testing provided a GP2 debut for a number of drivers, amongst them highly-regarded F3 Euroseries race winner Kamui Kobayashi, who wound up 14th for DAMS. The Japanese will be hoping for slightly more tomorrow as he moves across to ART Grand Prix.

Carroll ensured that new series champion iSport started the post-season in P1, topping the morning session in the #5 car which took Timo Glock to victory in the race and the championship on Sunday in Valencia. The Ulsterman was in fine form, lapping in 1min 28.036secs to fend off the challenge of Senna, Rodriguez and Conway.

Villa was only 0.3secs off top spot, but just 0.065secs ahead of Filippi, who had topped much of the session for DPR. The Italian was classified sixth at lunch, with team-mate Soucek seventh. Giedo van der Garde was the first of the non-2007 GP2 Series drivers on the timesheets, taking eighth place for Arden, just 0.682secs off Carroll's best, with Vitaly Petrov taking his race-winning Campos to ninth, ahead of returnee Clivio Piccione, who took tenth for FMSI.

Day two will see Karun Chandhok take his first laps at the wheel of the championship-winning iSport, running alongside Senna. Both men won races in 2007 and, just as with Carroll and Xandi Negrao on day one, will have a lot of attention focused on their performance. Ernesto Viso is expected to make his series return with Racing Engineering, while Buemi joins Zuber at Trident Racing. Campos Grand Prix,meanwhile, will have its 2007 line-up of Giorgio Pantano and Petrov back in harness.