Singapore - Olympic medallist Matt Kuchar fought back from a triple-bogey to win the Singapore Open on Sunday in a boost ahead of the Tokyo Games, while fellow Rio winner Justin Rose finished second.

The three men's golf medallists from the 2016 Rio Olympics appeared at the event, with their performances closely watched for clues about their form before the Tokyo Games start in July.

While Rio bronze medallist Kuchar of the United States and gold winner Rose of England had good tournaments, there was disappointment for silver medallist Henrik Stenson who finished 23rd.

Kuchar looked strongest throughout and went into the final day of the US$1 million event with a three-shot lead, but nearly let victory slip from his grasp on the par-five seventh.

His tee shot came up against the root of a tree and he missed the ball on his first bid to hit it clear.

His approach shot then flew left of the green and went out of bounds, but he eventually managed to hole a putt from 10 feet for a triple-bogey eight.

He staged a strong comeback however, with birdies on the 11th and 16th helping him push ahead of his closest rivals, before he sank a birdie putt to win the tournament with a final round one-under-par 70.

"Seven was a disastrous hole to make (a) triple-bogey," said the world number 24. "I felt like I was cruising along and had a four shot lead (at) that point and it was awfully comfortable."

But he added: "I'm awfully proud of being able to bounce back from adversity and being able to not let hard things get the best of me."

The win was a boost for Kuchar in his campaign to qualify for the Olympics.

Before the Singapore tournament, there were 12 Americans ahead of him in the world rankings, meaning it could be tough for him to earn a spot in Team USA.

The field will be finalised in June.

Rose made a strong charge on the back nine with back-to-back birdies on the 11th and 12th and a 70-foot birdie at the 14th, and picked up another shot at the 16th with a 15-foot effort.

He fired a final round 67 but his four-day total of 269 was still behind Kuchar's 266.

"Some second places hurt, some second places you feel good and this is more of a feeling good second place finish," he said.

Defending champion Jazz Janewattananond of Thailand took third place at the SMBC Singapore Open, which is sanctioned by the Asian Tour and Japan Golf Tour Organisation.