Northern Ireland’s Rory McIlroy will win a fifth Race to Dubai title at next week’s season finale after Max Homa won the Nedbank Golf Challenge.

The point standings after Homa’s first DP World Tour win means that world number two McIlroy, 34, cannot be caught by second-placed Jon Rahm.

American Homa converted his overnight one-shot lead into a four-stroke win at the event dubbed Africa’s major.

The 32-year-old Californian carded a six-under-par 66 to finish on 19 under in Sun City, South Africa, ahead of Ryder Cup rival Nicolai Hojgaard.

Hojgaard’s Danish compatriot Thorbjorn Olesen, who launched an early charge but slumped in the final holes at the Gary Player Country Club, finished on 14 under.

American Justin Thomas finished fourth, seven shots behind Homa after Englishman Dan Bradbury missed a putt on the final hole and slipped to fifth.

Scotland’s Colin Montgomerie finished the year atop the Tour’s Order of Merit a record eight times, although McIlroy is the first to reach five titles since the Race to Dubai format was introduced in 2009.

McIlroy is more than 2,000 points ahead of Rahm with just 2,000 available to the winner of next week’s DP World Tour Championship.

Homa, playing in his first tournament since the Ryder Cup in Rome last month, had a one-shot advantage at the start of the final round at the casino resort.

The world number eight was caught by Olesen, who went on the charge with six birdies in an outward 31, before an eagle on the ninth hole allowed Homa to retake the lead.

He then had a lucky break on the 14th when a wayward shot hit an official’s buggy and landed back in play before birdies on the next two holes, including a 38-foot putt on the 16th, stretched Homa’s lead to three.

“It was a crazy day because I got off to such a good start but Thorbjorn was playing unbelievably and kept pushing us along,” said Homa.

A double bogey by Olesen on the 17th increased Homa’s lead and ended the contest, with Hojgaard moving into second place.