Dario Franchitti accepted full responsibility for the collision that cost him the IZOD IndyCar Series points lead at Motegi, and apologized to the other drivers involved.
The reigning champion tagged Ryan Briscoe into a spin at a restart just before the halfway point of today's race. The two cars became entangled, with Franchitti damaging his front wing.
The incident also spoiled the races of both of Ganassi's satellite team drivers, with Graham Rahal sent spinning by Briscoe's rotating car, and Charlie Kimball forced to drive through the gravel. Both had been running with the leaders.
"The incident was totally my mistake, totally my mistake," said Franchitti. "I did a lot of hard work to get from ninth to fifth, and I'd been saving fuel the whole first stint.
"I made a risky move on the restart. I thought there was a gap and Ryan was going wide on the entry and that was that."
Franchitti, Rahal and Kimball's team boss Chip Ganassi was critical of the Scot in television interviews during the race, and Franchitti admitted his comments were fair.
"I apologized to Graham and I apologized to Chip," he said. "Briscoe and Charlie, I will apologize to when I see them.
"I own up to the mistake and Chip is right to be critical. It was a stupid move, and I shouldn't have done it."
Franchitti eventually got back up to eighth place. With title rival Will Power finishing second behind Scott Dixon, Franchitti now trails Power by 11 points with two rounds to go – and has lost the road course title to the Australian.
"Great job by the guys in the pits and I drove as hard as I knew how," added Franchitti. "I shouldn't have put us in that position. We still have it all to play for, but I keep making it more difficult."
He said he would not be dwelling on the error as every title fight contained missed opportunities and regrets.
"If you win or if you lose, you always look at the championship as a whole," Franchitti said. "Today, Loudon, Texas, Indy and on and on. You always look at these things, but Will can do the same with his races.
"That was a mistake today. Shouldn't have made it."