Takuma Sato says he "just living the dream" after claiming his second Indianapolis 500 in three years on Sunday.

The Japanese driver passed long-time race leader Scott Dixon shortly after the final pitstops and held on until a big crash for Spencer Pigot meant the race ended under caution for the final four laps.

At 43, Sato is the joint fifth oldest winner of the Indy 500, four years younger than the Unser brothers Al and Bobby, and he admits his late-career success proves that perseverance pays off.

“Look, 40-years-old, still driving, that’s just living in a dream,” he said. “I never even imagined a situation like this.

“People say 2012 was probably my peak and the best shot but we kept on going.

“We had a second chance in life. I say keep challenging, keep open the door, then you’ll get eventually the chance.

“I never thought my racing life would go on any longer than Formula 1. Now I’m competing here for more than 10 years.”

Indeed, Sato's seven-year stint in F1 yielded just one podium, ironically at Indianapolis in 2004, while in IndyCar he now has a total of six victories to his name.

However, after making what was the decisive pass on Dixon with 28 laps to go, Takuma admits running so long without a draft meant the final few laps might have been a struggle to hang on.

“We all knew and observed that Scott was the best competitor for really the entire two weeks,” Sato admitted.

“Dixie and Ganassi did a phenomenal job to always have the car in a competitive situation.

“He led the start, and then just disappeared. I was able to hang on at that time, I was playing with mixtures, seeing how much fuel mileage we could get out of it.

“So the first 100 laps, you wanted to be top-three/top-five, that was always my thought coming into this race. If I had the opportunity, yes, I want to lead it but then you’re using too much fuel.

“I realized that yes, we had a very competitive package and every single pitstop we made some changes. We went back and forth, back and forth because we went too much greedy, went too much conservative, went too much greedy again.

“And then finally for the last three stints, I was happy with the car. The second half of every stint I knew I was very strong, I had very good speed.

“However, after the pitstop when I took the lead [on Lap 157] I got a voice from the pit that I was using too much fuel, so I had to back off and lean the [fuel] mixture, and as you could see immediately Scott caught me.

“At this point, I had to switch back to maximum power and so when he was three or four car [lengths] behind, I would go back to the leaner mixture.

“And we were close. No doubt, that last yellow saved us, but even without it I was meeting the [fuel] number. Even if we had gone through [the final stint] entirely green, I think we would have been OK.

“However, still I think I would have been threatened from Dixie for the last few laps when he would probably have been 100 percent rich power. I had some of that in the pocket, but otherwise it was very, very close.”