O’Hara, who is attached to North Lanarkshire Leisure Ltd, started the final round of the Motocaddy Masters at Frilford Heath two shots behind the leader, Irishman Stuart Grehan, after opening with two 69s.
But, after recovering from a bogey at the first to card a 67 for an 11-under-par total, the 31-year-old ended up finishing two clear of the overnight leader to claim a £10,000 top prize.
“I’m delighted to win, it’s up there with the best moments of my career,” admitted O’Hara after holding off a chasing pack on the back nine that included Welshman Philip Price, who beat Phil Mickelson in the singles in helping Sam Torerance’s side win the 2002 Ryder Cup at The Belfry.
O’Hara, who has secured one of the spots available to PGA pros in next week’s $7 million Rolex Series event at Wentworth along with compatriot Gavin Hay, bounced back from that bogey start by following a second-hole birdie with an eagle at the fourth.
Out in 34, he’d got his nose in front and effectively clinched victory with a burst of three birdies in a row from the 13th.
“To play well down the last six holes when it was a tight leaderboard gives me a lot of confidence,” he added. “I have been working on trying to keep a level head under pressure, and I did that today. After the three birdies from the 13th, I knew I just had to keep it out of trouble on the last three holes.”
O’Hara was Scotland’s top-ranked amateur before turning professional and won on the EPD Tour, now the ProGolf Tour, in Germany before running out of money to fund his career.
He then trained to become a PGA professional and has recorded a number of notable victories on the Tartan Tour over the past few years, as well as landing the PGA Professionals Championship in Ireland last season.
“It will be a massive tournament and having won this week I will go there feeling great and I’ll enjoy it,” said O’Hara of joining the likes of Rory McIlroy, Tommy Fleetwood and Paul Casey in next week’s European Tour event. “I’m playing well enough to make the cut. Longer term my goal is just to keep improving as a player and see where it takes me.”
Craig Lawrie, Paul’s eldest son, birdied two of the last five holes to claim a share of 10th spot in the Frilford Heath opener on the third-tier circuit, finishing alongside Daniel Young of Kingsbarns after he also came home in 34.