Gil de Ferran led for all but eight laps to post his first Indy Racing League victory in the Radisson 225 in Fountain, Colorado.

In a rain-delayed race, De Ferran and Penske team-mate Helio Castroneves repeated their 1-2 finish in qualifying.

De Ferran, one of only four drivers to win back-to-back Cart championships, is in his first season on the IRL circuit.

"The car was absolutely fantastic today," de Ferran said.

"It was good in traffic. I could drive low or high. The guys did a great job in the pits.

"We've been knocking on the door since the beginning of the year, and I'm glad to get one under my belt."

De Ferran finished 1.4 seconds ahead of Castroneves, winner of the last two Indianapolis 500s, and two seconds ahead of Sam Hornish Jr.

The result leaves the two Penske drivers at the top of the drivers' championship, with Castroneves on 267 points and De Ferran on 235.

Hornish Jr, who led the series early in the season has 206, with Brazilian Felipe Giaffone. fourth on 202.