Johnny Cecotto - Photo Credit: Alastair Staley/GP2 Media Service

Johnny Cecotto - Photo Credit: Alastair Staley/GP2 Media Service

Johnny Cecotto Jr was the surprise pacesetter in GP2 practice in Monaco after a superb final lap put him more than six tenths clear of the rest of the field.

Fabio Leimer had been in top spot when the checkered flag came out at the end of the 30 minute session, but championship leader Davide Valsecchi strung a good lap together on the slower prime tyre to move five thousandths of a second ahead.

Barwa Addax driver Cecotto then followed the Italian across the line on the supersoft rubber, going a sizeable 0.67 seconds faster. Monaco had been the scene of Cecotto's only GP2 Series points finish prior to the current season, when he finished fourth in the 2010 sprint race.

Giedo van der Garde finished the session in fourth behind Valsecchi and Leimer. The Caterham Racing driver had been top with five minutes to go until he lost control at Rascasse, getting into a slide and nosing the barrier to bring an early end to his session.

He wasn't the last driver to have a moment, with Cecotto's teammate Josef Kral spinning on the exit of the swimming pool complex, but somehow keeping his car out of the barrier by a matter of millimetres. He got his car spun back around and facing the right way, but stalled it. This had looked to bring an end to the session with the yellow flags out, but his car was quickly hoisted out of the way to enable those fast times from Valsecchi and Cecotto.

Jolyon Palmer was fifth fastest after an early switch to the supersoft tyres, as the Briton hopes that a rebuilt car will have brought an end to the mechanical gremlins that have blighted his season so far. Drivers this weekend have two sets of the option compound as opposed to the usual one, and in a rule change for the remainder of the season, they are free to use the two compounds in any session during the weekend.

Luiz Razia was sixth after spending time in P1, ahead of local boy Stefano Coletti and Brit Max Chilton. Nathanel Berthon was ninth with Kral in tenth.

Giancarlo Serenelli's session ended early, making a similar mistake to Van der Garde at Rascasse. He didn't end up bottom of the pile though, because Esteban Gutierrez crashed into the tyres at Ste Devote within the first five minutes, before he was able to get a competitive time on the board.

Qualifying takes place at 15.55 BST, where the field will be split into two groups for the first time. A ballot determined that Group A, containing even-numbered drivers such as Gutierrez and van der Garde, will run first for a 14 minute session, followed by Group B containing the likes of Cecotto, Valsecchi, Razia and Calado.