The Brazilian joined AJ Foyt, Al Unser Senior and Rick Mears, his former mentor at Team Penske, as the only four-time winners of the race. Mears was the last driver to so in 1991.

Castroneves won his third 500 in 2009 and has been chasing win number four ever since.

At 46 years old, in his first season no longer driving for Roger Penske, he held off Alex Palou to win the 105th running of the race in front of 135,000 fans - the most at any sports event in the world since the pandemic began 18 months ago.

The number represented 40 per cent of the speedway's capacity and was agreed upon by health officials.

A year ago, no fans were allowed for the race that was delayed from May to August. This year, celebrities were back and fans were everywhere and they were treated to a win by one of the most popular drivers in Indy 500 history.

"I love Indianapolis! You guys don't understand it! The fans, you give me energy," Castroneves said.

Castroneves was also part of the winning Rolex 24 Daytona sports car team in January, taking the prestigious sports car event for the first time.

"I've run two races this year and won two races, I'd say that's pretty good," said Castroneves, who noted that Tom Brady won the Super Bowl this year and 50-year-old Phil Mickelson won the PGA Championship last week.

It was a stark contrast to the recent theme of young drivers taking over IndyCar, which now has six different winners through six races this season. Three of them have been first-time winners and four are drivers aged 24 or younger.

Castroneves found himself in a closing duel with one of the young stars, 24-year-old Spaniard Alex Palou, but he passed Palou for good with two laps remaining and beat him by 0.4928 seconds for the victory.

Former Penske teammate Simon Pagenaud, the 2019 Indy winner, was third, followed by Pato O'Ward, the 21-year-old budding IndyCar star.

Australia's Will Power finished 30th.

Australian Associated Press