Rory McIlroy’s record U.S. Open win let a gambler cash in on a 10-year-old bet with plenty of time to spare.

An anonymous Irishman bet on McIlroy to win a major tournament before he turned 25 after playing with the youngster 10 years ago, according to the website DigitalJournal.com.

McIlroy, of Northern Ireland, won this weekend’s U.S. Open at 22 years, 1 month old. The gambler collected more than $40,000 on the 500-1 shot.

McIlroy’s father placed a similar wager seven years ago that will pay 500-1 if his son wins the British Open before turning 25.

Gerry McIlroy and three friends have $650 at stake with a chance to win more than $80,000 each.

The British Open will be held this year July 14-17 at Royal St. George’s in England.

According to the website, Rory McIlroy won $1.26 million at the U.S. Open and will pocket $1.38 million if he wins the British.

McIlroy became the youngest U.S. Open winner since Bobby Jones in 1923 with a record score of 16-under-par.

He set 12 U.S. Open records in his win at Congressional Country Club, including the lowest winning score in the tournament’s 111-year history.

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Las Vegas oddsmakers have installed McIlroy as the favorite to win the British Open. He opened at 6-1 at the Las Vegas Hilton’s Race and Sports Book.

Lee Westwood of England is the second-favorite at 10-1, followed by Tiger Woods and Luke Donald, the No. 1 golfer in the Official World Golf Ranking, at 15-1.