Kristoffer Broberg held his nerve to defeat Patrick Reed in the first play-off hole at the BMW Masters and secure a maiden European Tour win.
Both the Swede and Reed - who had led by a shot with two holes of the final round to play, thanks partly to sensationally holing out from 100 yards on the 15th - missed birdie attempts that would have sealed victory at the 18th.
As a result, each man finished on 17 under to send a thrilling climax into a shootout.
On the first additional hole, the 18th, Reed found a bunker with his second shot but an excellent recovery shot cranked the pressure up on Broberg.
However, the world number 149 calmly rolled in a 12-foot putt to make birdie and rocket up to 12th in the Race to Dubai standings, which Rory McIlroy - who was not present in Shanghai - continues to lead ahead of Danny Willett going into next week's season-ending World Tour Championship in Dubai.
Willett, tied for 28th, missed the chance to overhaul McIlroy, although he has reduced the Northern Irishman's lead from 74,213 points to 1,613.
Reflecting on his win, Broberg said: "It's a dream come true.
"I've worked all my life for this. I have no words. I don't know what to say."
Overnight leader Thongchai Jaidee and Byeong-hun An missed birdie putts at the 18th that would have seen them join Broberg and Reed in the play-off, the duo finishing on 16 under along with Henrik Stenson and Lucas Bjerregaard.
English duo Justin Rose and Paul Casey were a shot further back, while Sergio Garcia found water twice on the final hole as a double-bogey six meant he finished four off the pace.