Australia's Richie Porte holds a one-second lead after the opening day of the Criterium International on Corsica.
The Team Sky rider won the 7km time trial stage in nine minutes, 10 seconds, edging out Italian Manuele Boaro and American Tejay van Garderen.
Britain's Chris Froome, Porte's team-mate, is fourth, two seconds back.
The two-day, three-stage race began with an 89km ride, won by Theo Bos, and finishes with Sunday's 176km race to a summit finish at Col de l'Ospedale.
Bos outsprinted Nacer Bouhanni and Jonathan Cantwell in the opening stage but Porte finished in the main bunch and his superior time-trialling ability saw him leap to the top of the standings in the afternoon.
The third and final stage should also suit the 28-year-old, who won the week-long Paris-Nice race earlier this month, and Froome, who was runner-up to Sir Bradley Wiggins in the 2012 Tour de France.
"I will be delighted to help Chris [on Sunday] but I'm sure he'll be very happy to help me too," said Porte.
"It was quite a technical route this afternoon, and not my sort of a course, but I've done a lot of work on my time trial position, and that's definitely paid dividends.
"We're in a good position with me in the lead and Froomey sitting just a few seconds back. It's going to be quite tight [on Sunday] because there's a lot of good riders close to us.
"We came in with Froomey as our leader so if he's got good legs and I don't then I'll be more than happy to ride for him. Obviously, I'd like to finish the job off if I can, but as long as Team Sky win it'll be a great day and we'll all be happy."
Defending champion Cadel Evans, who is an excellent climber, almost fell off his bike on a descent in the time trial and finished 68th, 45 seconds adrift.
The stage finishes at the top of the Col de l'Ospedale, after a 14.1km climb at an average gradient of 6.2%.
The mountain overlooks Porto-Vecchio where the 2013 Tour de France will start on 29 June.