Indianapolis ? Kurt Busch won the International Race of Champions title with a fourth-place finish Saturday behind Jimmie Johnson in the season finale.

“It’s just an honor to drive in this series, for one thing, but to compete against the best of the best and beat them one day — I just dreamed about this day, and it came true,” Busch said.

The IROC rookie started with a second-place finish in Daytona, won at Talladega, finished third at Joliet and wrapped up the $250,000 title despite starting last in Saturday’s 12-car field.

The race began with IndyCar Series star Helio Castroneves, last in the points coming in, starting from the pole. The two-time Indianapolis 500 winner got off to a great start and held the lead as Kevin Harvick and then Johnson were less than a second from the Brazilian’s rear bumper.

A piece of debris on the 21/2-mile oval brought out the only caution flag of the 40-lap race just past the halfway mark — a bad break for Castroneves.

Caution flags don’t count in the all-star series and, on the restart of lap 21, Johnson got the drop on the leader and pulled alongside as they drove through the first two turns. Johnson then pushed past with Harvick’s help to take the lead for good.

Castroneves suddenly found himself in the midst of a NASCAR-style draft and was kicked all the way back to seventh.

“I knew it was going to be my only opportunity to get a pass done,” said Johnson, also an IROC rookie. “I worked by everybody and got to Helio. He was doing a great job, and I didn’t think I had anything for him.

“But when the caution came out, I knew I would have about a lap to get something done. Harvick helped me down the straightaway and helped me get by, and it helped him into second place.”

Castroneves, who wound up eighth, said, “I just need to know how to find the draft. Those guys, side-by-side, I don’t know how they do it.

“Harvick was just pushing Jimmie like crazy (on the restart), and I was thinking, ‘How is this possible?”‘

Harvick was second, 0.696 seconds — about four car-lengths — behind Johnson.