Helio Castroneves didn't appear to be too bothered by the fact that his primary car had been damaged in a transporter fire on the way to this weekend's IndyCar Series round at Infineon Raceway, jumping into his back-up to go fastest on the first day of practice for the PEAK Antifreeze & Motor Oil Indy Grand Prix of Sonoma County.

The Brazilian, who finished second at Infineon last year, lapped the revised 2.303-mile circuit in 1min 17.1703secs during the afternoon session, bettering Tony Kanaan's effort of 1min 17.3920secs from the morning.

"If there is a team that knows how to rebound, it's Team Penske," Castroneves enthused, "Again, they did a fantastic job. They tried to make sure I don't feel a difference and, to be honest, I don't. The car is basically the same.

"I keep joking that the seat I loved burned up, but the one I have here is very similar. It's a good start for what's been a tough two days. To finish the day [in P1] is a great deal, but tomorrow is a bigger deal and so is the race, so we're going to keep working hard. I'm not surprised to be fast as we tested here last week for the first time since about January. I didn't test, and it wasn't even Ryan, it was [Penske ALMS driver] Romain Dumas, but it just proves that a little bit of laps around this place helps a lot. We may not have gone fast, but it helps eliminate some things we may have tried today."

Kanaan was happier than of late with his practice performance, despite being pipped to top spot by his countryman.

"It was a good day for the Team 7-Eleven guys," he confirmed, "We worked on the qualifying set-up in the morning, and concentrated on the race in the afternoon session. I'm pretty pleased with how today went.

"We're going to try and maximise our situation and finish as high as we can in the championship, but I'm just working on winning some more races for the team. After you win the championship, finishing second, third, fourth, or fifth I don't think will make a big difference. Obviously, we are working toward a real possibility that there will be a big fight between me and Dan [Wheldon] for the third position in the championship but, if you look at Helio and [Scott] Dixon, they are so consistent right now that I think it's going to be really difficult to catch them. I'm focused on winning races."

KV Racing Technology team-mates Oriol Servia and Will Power continued to underline the road course potential of the series 'newcomers' in third and fourth respectively.

"It helped KV Racing Technology to come here to test last week," the Catalan admitted, "It brought us closer to the established teams, which is where we want to be - but we still need to keep working. It's getting very close to the end of the season and everyone is very eager to win, so it is good that we are in the ballpark. We still have all day tomorrow and then the race on Sunday before it is decided and, until then, we will keep on learning and trying new things with the car."

Power admitted that he was slightly surprised to have been as high as he was, after encountering traffic throughout the day.

"It was very difficult to get a good lap in with so many cars on track, but the car was quick," he noted, "We still need to work some things out to make the car a little bit better, but our aim for tomorrow is to not only make the Firestone Fast Six, but to be right up at the front."

Perennial runner-up Vitor Meira slotted into fifth spot for Panther Racing, another to have been buoyed by a strong test at Infineon earlier in the month.

"We had a good day today, and we knew we would have a good package after the test last week," the Brazilian reported, "Luckily, that translated into today. There was an issue this morning with our braking, but the Panther guys were able to fix that during the break, and you could see how quick we were this afternoon. We're happy with fifth overall and looking forward to making a run at the Firestone Fast Six tomorrow."

Points leader Dixon, who heads Castroneves by 78 points in the championship, was seventh, one spot behind the Brazilian's team-mate, Briscoe, who also lost his primary race car to Wednesday's truck fire.

"Qualifying on road courses this year has been really competitive, so we want to be sure that we know what we have in the car for tomorrow," the Australian explained, "We're happy with the car, even though we weren't at the top of the speed charts. We put on a new set of tyres right before the end of the session, but we were unable to post a time, so we'll just continue working in the morning and hope for the best come qualifying in the afternoon.

"I have to say that I'm super proud of our crew with the way that they have handled the adversity in the wake of the transporter fire. They have been working really hard since they landed yesterday to make sure that I have what I need in the car, and I have no complaints."

Danica Patrick produced a stronger road course performance than of late, sitting in eighth place, while Andretti Green team-mates Marco Andretti - resplendent in a new Star Wars livery - and Hideki Mutoh rounded out the top ten.

Champ Car converts - and Infineon rookies - Justin Wilson and Bruno Junqueira were next up, ahead of Ryan Hunter-Reay, Mario Dominguez and Enrique Bernoldi as the recent test proved its worth to those not au fait with the Sonoma circuit. Wilson, however, wasn't among them.

"We just spent the day working on the set-ups and are about where we thought we would be performance-wise," the Briton said, "It would be nice for us to be a little bit closer to the front, but we'll study the data tonight. Not only did we not race here last year, but everyone tested here last week so we knew we would have our work cut out for us here.

We didn't get to come here because we were still building this car. It's a new car - new to us anyway - and was previously used by Jon Herb. It had been sitting in the shop for a few months, being built when there were a few extra hours available - which wasn't often - but, for some reason, my seat didn't fit as well in this chassis, so we spent some time making some modifications for that. .

"We thought we had been making improvements, but these other guys weren't standing still either. We've got more work to do to try and get the McDonald's car to feel a bit better and see if we can do what we did at Mid-Ohio and sneak it up there, keep scraping through the qualifying rounds and make it to the final six."

Ernesto Viso, Buddy Rice, Mario Moraes, Dan Wheldon - surprisingly down the order - and returnee Tomas Scheckter rounded out the top 20.