Luca Filippi was left to wonder what could have been following the Honda Indy 200 at Mid-Ohio.

The 27-year-old veteran GP2 driver from Italy and Helio Castroneves of Team Penske advanced the most positions in the 90-lap race on the 2.258-mile, 13-turn road course.

Filippi, making his IZOD IndyCar Series debut in the No. 98 Barracuda Racing car, started 24th and finished 16th. Castroneves placed sixth to increase his championship points lead to 31 over Scott Dixon of Target Chip Ganassi Racing.

Competing in the second group of the first round of knockout qualifying, in which six of the 12 cars advance, Filippi slid off course in Turn 12 on his first lap. That brought a red flag, which cost Filippi his two fastest laps of the 10-minute session. Once the car was checked and cleared by the crew on pit lane, Filippi was turning laps that would have put him fourth in the group if not for the penalty.

In the caution-free race, he was quick and finished on the lead lap.

"It was good to drive and I think we had a very strong pace," said Filippi, whose initial seat time in the Dallara chassis came during an Open Test on July 31. "Obviously, starting from last with no yellows was difficult to get a better result. I'm a bit disappointed with the start because I was already more than 20 seconds behind the leader and that makes everything more difficult.

"On the last lap, I thought I was racing against (Takuma) Sato but he was actually one lap down so that's a shame, but apart from that, I think we did everything we could to improve our position. We made good strategy and the pace was extremely good.

"Overall, my first race in IndyCar was very exciting. I'm looking forward to more opportunities and I'm proud of all the work we've done as a team."

Castroneves missed qualifying on the first five rows for the fourth time this season, but was running in the top 10 early on. During the final 15 laps, he and Dixon engaged in a spirited battle for sixth, with Castroneves finishing three-tenths of a second ahead at the checkered flag.

“If you would have told me we would have finished in the top 10 today, I would have said you were crazy," said Castroneves, who remains the only driver to complete every lap (1,843) this season. "We made great strategy calls throughout the race. I know that it was only a sixth-place finish but it could win the championship at the end of the year. I have said all along that we will continue to do our thing and not change a thing and it will pay off at the end of the day."

Davison also impresses

James Davison, another first-time series competitor, also had a solid race in the No. 18 Sonny's BBQ car for Dale Coyne Racing by finishing 15th. He was running as high as sixth during pit stop sequencing.

“I cannot thank Dale Coyne and all of my lifelong supporters for helping me realize this dream of becoming an IndyCar driver,” said Davison, who won Firestone Indy Lights races at Mid-Ohio in 2008 and '09. “To practice, race and most importantly to be competitive with all of the new things one has to learn on one of these weekends is an amazing experience.”