Jon Lancaster led the way in the opening practice for round six of the Formula Renault 3.5 Series at Le Mans.
Lancaster's Friday morning time of 1m27.620s provided a 0.1s advantage over GP2 man Edoardo Mortara.
The Italian, replacing Brendon Hartley, is set to embark on his first outing with Tech 1 Racing, having made one previous World Series start for SG Formula.
Fairuz Fauzy was third fastest for Fortec Motorsport and again optimistic over his race prospects.
Friday's second, hour-long, practice in the afternoon was disrupted by torrential rain and three red flags. Bertrand Baguette benefited from some intense early laps when the circuit was still dry to top the timesheets on 1m27.833s, almost a second clear of Draco team-mate Marco Barba.
Heavy rainfall ten minutes into the session prohibited any improvements in lap times, leaving championship leader Marcos Martinez unable to progress on an unrepresentative 25th position.
Lancaster impressed in the wet running, it being his first opportunity to sample the car in such conditions. The Carlin duo of Monaco winner Oliver Turvey, and expected Toro Rosso Formula 1 race driver Jaime Alguersuari, were equally formidable.
James Walker, second in the standings and six points adrift of Martinez, sat out the morning as he recuperated from a nasty injury to his throat, caused by a lodged piece of steak on Wednesday.
"If you had asked me this morning if I would be racing I would have said 'no chance,'" said Walker. "I was examined with an endoscope yesterday afternoon and I feel really rough, my neck is killing me. They don't give you a full anaesthetic, only a sedative, and I think I have had a bad reaction to that as well.
"I am just doing a few laps to see how I feel. I put a neck support on as I am having trouble supporting my head. When you're second in the championship, if by racing you pick up a point, then it is worth going out. I was in hospital at Le Mans on Wednesday night, and I am only now having my first food in two days."
Walker's P1 Motorsport team have their 2008 champion, Giedo van der Garde, on hand over the weekend to assist with the progress of the number six car, handled by the improving Russian Daniil Move.
In his maiden World Series event, current Racing Engineering GP2 driver Dani Clos ended the day in 11th and 19th.
"I am one of the least experienced guys in GP2 in terms of kilometres covered, as I did not take part in the pre-season GP2 Asia series," said Clos.
"It was, therefore, a good call when Epsilon Euskadi contacted me to ask if I could drive here. The differences between the World Series and GP2 cars that I am getting used to are the weight distribution and how to use the brakes.
"I have raced at Le Mans before in the Formula 3 Euro Series last year and finished P2 - not P1 because the race didn't go to full distance. I really don't mind what the weather does here for the races. My second World Series race at Portimao will be really important as it is also hosting the last GP2 race."
Pos Driver Team Time Laps
1. Jon Lancaster Comtec Racing 1:27.620 24
2. Edoardo Mortara Tech 1 Racing 1:27.751 + 0.131 19
3. Fairuz Fauzy Mofaz Fortec Motorsport 1:27.808 + 0.188 21
4. Bertrand Baguette International Draco 1:27.872 + 0.252 26
5. Miguel Molina Ultimate Motorsport 1:27.949 + 0.329 20
6. Marcos Martinez Pons Racing 1:28.054 + 0.434 24
7. Chris Van Der Drift Epsilon Euskadi 1:28.224 + 0.604 20
8. Charles Pic Tech 1 Racing 1:28.339 + 0.719 21
9. Jaime Alguersuari Carlin Motorsport 1:28.439 + 0.819 24
10. Filip Salaquarda Prema Powerteam 1:28.469 + 0.849 20
11. Dani Clos Epsilon Euskadi 1:28.478 + 0.858 21
12. Oliver Turvey Carlin Motorsport 1:28.525 + 0.905 24
13. Daniil Move P1 Motorsport 1:28.628 + 1.008 27
14. Pasquale Di Sabatino Rc Motorsport 1:28.913 + 1.293 24
15. Guillaume Moreau Kmp Group / Sg Formula 1:29.224 + 1.604 23
16. Adrian Zaugg Interwetten.Com Racing 1:29.254 + 1.634 23
17. Greg Mansell Ultimate Motorsport 1:29.439 + 1.819 22
18. Sten Pentus Mofaz Fortec Motorsport 1:29.560 + 1.940 20
19. Julian Leal Prema Powerteam 1:29.759 + 2.139 23
20. Anton Nebylitskiy Kmp Group / Sg Formula 1:30.047 + 2.427 21
21. Marco Barba International Draco 1:30.122 + 2.502 22
22. Mihai Marinescu Interwetten.Com Racing 1:31.446 + 3.826 7
23. Federico Leo Pons Racing 1:31.645 + 4.025 15
24. Cristiano Morgado Comtec Racing 1:33.164 + 5.544 22
25. James Walker P1 Motorsport No time 0