Sam Hornish Jr. turned the fastest laps for the Indianapolis 500 since testing began, leading four drivers under 40 seconds on Thursday on the famed 4km oval on a damp, cold day with gusting winds.
His 39.6844 seconds was more than a 10th of a second faster than his closest rival, defending champion Dan Wheldon, averaging 364.9kph (226.789mph).
That solidified Hornish as the early favorite to win the pole in Saturday's opening round of time trials for the May 28 race.
"We're making sure we've got the car good for more than one lap," said Hornish, who came up just short of pole-winner Tony Kanaan in last year's four-lap qualifying run.
Thursday was the third straight day that Hornish has been the fastest driver on the track, but this one was most significant because of the conditions when he did it.
"We went out and ran when it was about as windy as it was all day," Hornish said. "When the wind is gusty like that, it can get a little scary at times. The wind picks up the car and moves it around a little. But it was about as comfortable as it has been since we got here."
Hornish, a two-time IRL IndyCar Series champion, has never finished better than 14th in the America's premier auto race.
Eighteen drivers made it onto the track Thursday, with Wheldon second fastest at 39.8075 seconds, followed by Castroneves at 39.9030, Scott Dixon at 39.9451 and Dario Franchitti at 40.0460.
There were two more incidents on Thursday, with Buddy Rice, the 2004 Indy winner, bruising both knees in a hard crash and Marty Roth spinning harmlessly. Rice, who missed last May's 500 because of injuries sustained in a crash during practice, was not immediately cleared to drive and will be re-examined by track doctors Friday.
After having practice sessions Tuesday and Wednesday cut short by rain, the start of Thursday's session was delayed by rain for two hours and the session was cut short by about 20 minutes when rain came again.
Paul Tracy announced a five-year contract extension with Forsythe Racing on Thursday, renewing his commitment to the Champ Car World Series.
Tracy, 37, is the circuit's active leader in starts (237), victories (30) and podium finishes (69), but he's also raced stock cars on NASCAR's second-tier Busch Series and in the US Grand Am circuit in recent months.
Tracy, who won the 2003 points title in his first year with Forsythe, will race this week in the Champ Car Grand Prix of Houston. He's flirted with the idea of moving to stock-car racing full-time, but said he's always preferred open-wheel, road-course racing.
"I've kind of gone through a thing at this point in my career of deciding what I want to do, what direction did I want to go," Tracy said. "I was going to try stock cars, racing Grand Am cars, doing some endurance racing, but this is still what I love to do."
Tracy, in his 16th season on the Champ Car series, was also swayed to stay because he's optimistic that the circuit will soon merge with the rival IRL.
"I don't really know if the unification is going to happen or not," the Canadian said. "But I'm hearing the same things that you guys do. If it happens, I think it will be great. If that happens, I'd like to be a part of the landscape."
A merger would also give Tracy a straighter path back to the Indianapolis 500, the IRL's signature event. In 2002, Tracy finished a disputed second to Helio Castroneves, claiming he passed Castroneves on lap 199 before a yellow caution light appeared. But Castroneves' victory stood despite appeals from Tracy and then-team owner Barry Green.