In the end, Manassero was exhausted and ultimately elated.
The 19-year-old Italian won his third European Tour event when made a 15-foot eagle putt on the third extra hole on a day that also crowned the new Race to Dubai winner.
After a final-round 65, Rory McIlroy surged into solo third, three shots out of the playoff, but the €289,297 ($367,664) paycheck was enough to clinch the European Tour money title, with two events remaining on the schedule. He needed only a top 10 this week to capture the seasonlong Race to Dubai.
“It’s been an extremely long day,” Manassero told reporters afterward. “The adrenaline kept me going and the key was starting really well this morning. … This year has been a tough year for me going through a few swing changes, but it has been amazing this week. I’m glad this came in such a great tournament.”
Both players finished at 13-under 271.
Oosthuizen, vying for his third victory of the season, had a chance to close out the win on the second playoff hole, but his 4-foot birdie putt lipped out.
Players scrambled to complete much of the third round after lengthy storm delays on both Thursday and Friday at Sentosa Golf Club. Manassero, who became the first player to win three times on the circuit before the age of 20, took a two-shot lead into the final round after a third-round 64.