Australian Ryan Briscoe's remarkable run of completed laps in this year's IndyCar series has come to a shuddering halt in the Indy Challenge on Saturday.

Briscoe had completed every prior lap this season and was leading the season points ladder when the race began but hit the wall and was knocked out in lap 26 of the 300-lap feature at the Richmond International Speedway.

The accident forced Briscoe to finish 19th in the 20 car field, with New Zealander Scott Dixon holding off teammate Dario Franchitti in the final 20 laps to claim his third win of the season.

"I lost the rear on the exit of two. I was really battling an understeer problem," Briscoe said.

"It's just so disappointing."

Dixon's second victory at Richmond was the Kiwi driver's 19th IndyCar Series victory, matching the all-time record for the series that was formed in 1996.

"It was about patience," Dixon said. "It was really tough to pass. I have to hand it to Dario. He was making it intense. We were able to save a little more fuel than him and that was the difference."

Franchitti settled for second with American Graham Rahal third for his first IndyCar oval podium.

Despite finishing second to Dixon, the Scotsman moved two points ahead of his Ganassi Racing teammate in the season points championship.

"The points lead is definitely a bright spot," Franchitti said. "A lot of people had worse days than we did."

Japan's Hideki Mutoh was fourth with Danica Patrick finishing fifth.

Franchitti and Dixon led after the first set of pit stops and received a break midway into the race when England's Mike Conway crashed to bring out a caution flag just as they needed fuel.

Refuelling under the slow-speed caution period allowed Dixon, Franchitti and Rahal to gain an edge on the remainder of the field.

Dixon, whose wife is expecting a baby in three weeks, jumped into the lead with Franchitti second and Rahal third.

Patrick made her last pit stop with 74 laps remaining, hoping for a full-speed sprint to the end that would allow her fuel mileage edge to put her in position for a second career triumph.

But when Indianapolis 500 winner Helio Castroneves of Brazil hit the wall with 52 laps remaining, the three leaders were able to make their last pit stops under caution and Dixon edged Franchitti from the pits with Rahal third.

Dixon came upon slower traffic with 20 laps remaining but Franchitti could not make a pass and the positions stayed the same to the finish.

The 18-race season reaches its midpoint next week at Watkins Glen, New York.AFP