A 200/1 outsider before The Open in 2010, which was celebrating the 150th anniversary of its founding, Oosthuizen announced himself on the global stage by taming the famous St Andrews links to be crowned Champion Golfer of the Year.
He never looked back after taking the lead on the Friday and ultimately clinched the Claret Jug by seven shots for his maiden major title - and a place in Open history.
So impressive was his unexpected triumph, it made the fact that he had missed the cut in his previous three Open appearances look all the more bizarre.
And when The Open returned there five years later, he came within a whisker of doing it all over again. To celebrate Oosthuizen's birthday, we have taken a look back at his remarkable journey to becoming Champion Golfer.
Following in the footsteps
The lineage of great South African golfers who have triumphed in The Open, is easy to chart from Bobby Locke through Gary Player to Ernie Els.
And Oosthuizen admits his heroes have helped him become the major winner he is – and not just as inspiration.
Oosthuizen’s early golf career was supported financially by Els’ Foundation and he turned professional back in 2002. He impressed on the Sunshine and European Tours but consistently underperformed at the majors.
But that all changed that famous week in 2010.
Storms to success
Oosthuizen came into that week at St Andrews ranked outside the world’s top 50 but produced stunning golf to claim a halfway lead.
He shot a 65 on the opening day in fine weather, then backed that up with a 67 in the rain on day two – his two-day total of 132 tied the record in The Open at St Andrews.
And over the weekend he was far too solid for the field and ended up winning by a whopping seven shots from Lee Westwood and Paul Casey.
His 272 was the second lowest four-round total in St Andrews history and owed much to a red dot he drew on his glove to maintain his focus all week.
A dream come true
“St Andrew is completely different to any other links courses you play,” he said. “It’s the bunkers, and the conditions, the wind and rain.
"Massive greens to hit to so if you hit it well that week you will have loads of birdie opportunities but you have to hit it really well to have short ones.
“I played as an amateur and went in so many bunkers. Everything changes when the weather comes in. It’s a really great thing to win, something you have dreamed of, it’s everything and more.
“Having South Africans before me, Bobby, and Gary and Ernie, it’s a trophy I really wanted my name on and it’s a great thing to be able to say you have won The Open.”
The nearly man
Oosthuizen has been far from a one-hit wonder since his victory, though, even if a second major title has so far eluded him.
He came mighty close in 2015 when The Open returned to St Andrews – only edged out by Zach Johnson in a play-off when his putt on the 18th to force extra holes lipped out.
And in 2017 in the PGA Championship, the South African claimed the unenviable Grand Slam of runners-up finishes.
But his antics on the flight home proved he can certainly see the funny side.
And with plenty of miles left in the tank, you can be sure Oosthuizen will be challenging for majors again soon. He is certainly always there or thereabouts.
He was tied 28th at Carnoustie in 2018 before finishing in the top 20 at Royal Portrush in The 148th Open - and don't bet against him being in contention for the return of the Claret Jug to St Andrews in 2021 for the 150th edition.