Having missed Sunday’s race in Monaco to compete at the Brickyard, Alonso belied his lack of oval racing experience by running at the front throughout and leading on several occasions. But with 21 laps to go, as his was vying for sixth place in the leading pack, smoke began to pour from the rear of his McLaren-entered car.
“It’s a shame - we deserved at least to finish the race,” said Alonso, who was given a standing ovation by the 300,000 spectators in attendance when he clambered out of his bright orange car.
“Who knows what position we could have been?
"The whole day has been a nice experience from the presentation to the racing. The performance was good, we were up there and leading at the red flag.
"It was a nice surprise to come here with the big guys and be competitive.”
For the second year in a row the 500-mile race was won by a former F1 driver, with Takuma Sato – a veteran of 90 Grands Prix with one podium finish to his name – taking the spoils for the same Andretti squad that had also run Alonso’s car.
Another former Grand Prix driver - ex-Manor pilot Max Chilton - finished fourth.