Rory McIlroy can do his father proud, and make him much richer, on Sunday by winning the British Open at Hoylake.

For 10 years ago, 25-year-old McIlroy’s dad Gerry and three friends each placed a STG100 ($A180) bet at odds of 500/1 that his son would become Open champion before he turned 26.

The end result of that would be an overall jackpot of STG200,000 ($A365,000), for the quartet, while McIlroy would pocket a cool STG1 million ($A1.83 million) for winning the third major of his young career.

The Northern Irishman already has two major titles under his belt — the first in the US Open at Congressional in 2011 and the second in the US PGA Championship at Kiawah Island the following year. He won both of them by eight shots.

On Sunday he will take a six-shot lead into the final round at Hoylake and few people would bet against him winning again despite the last day collapse that cost him the Masters title in 2011 when he led by four before Sunday.

McIlroy’s father is not the only one eager to see him complete the job.

One punter stands to earn STG80,000 ($A146,000) if he closes the deal, according to British bookmakers Ladbrokes.

Back in 2005 a shop customer had the foresight to place a STG200 ($A365) wager on a then-teenage McIlroy to win The Open before 2015 at odds of 250/1.

He also placed a second bet on the Northern Irishman to do so before he turned 50 at 150/1 — leaving him to collect just over STG80,000 should McIlroy hold aloft the Claret Jug on Sunday for the first time.

The bookies are already sweating about a potential STG2 million ($A3.65 million) total payout should he be victorious at Hoylake.