Jenzer's Nico Muller laid down a marker for the rest of the GP3 Series field by comfortably topping today's opening practice session.
Muller's best time of 1m38.181s left him nearly 0.3sec clear of closest rival and teammate Pal Varhaug. A quickest second sector on the final lap suggested that the latter might have been able to go faster still, but his car developed a problem before he could finish the lap and left him crawling back to the pits.
Series leader Esteban Gutierrez was third ahead of Status' Robert Wickens, with Jenzer's Marco Barba the quickest of the three drivers making their series debut this weekend in fifth.
Another newcomer, Carlin's Antonio Felix Da Costa, had a tougher introduction to the series when he crashed at the first corner five minutes before the session ended.