Triple Supercars champion Scott McLaughlin has lamented a mistake which he felt cost him a top 10 finish in his maiden Indianapolis 500 on Sunday.

The New Zealander was on the fringe of the top 10 throughout the early stages of the iconic 200-lap race at Indianapolis Motor Speedway.

A drive-through penalty for speeding in pit lane halfway through the race however left the Penske Racing driver to fall back in the pack, eventually finishing 20th.

While McLaughlin's finish made him the highest-placed rookie in the field, he felt the result could've been even better.

"My race, look, really happy to get the rookie of the year honours," he said.

"I would have loved to have been a little higher. I feel like I could have been in the front group.

"I don't know if I would have won the race, but I certainly feel I could have been a factor in the top 10.

"Bittersweet day for me."

The 500-mile race was also one to forget for McLaughlin's Australian teammate Will Power.

While ex-Penske driver Helio Castroneves stole the show by winning his fourth Indy title, Power limped home a lowly 30th after spinning late in the race.

It capped a bad month for the 2018 Indy 500 winner, who had to start on the final row of the grid after just barely scraping through qualifying.

Former Supercars driver Simona De Silvestro was classified 31st after her day ended on lap 169 with a brake issue.

New Zealand star Scott Dixon, who started the day from pole position in his quest for a second Indy 500 win, finished 17th after a pit lane drama of his own early in the race.

The next stop in the 2021 IndyCar series is in Detroit on June 12-13.