It was a mouth-watering clash of the continent's two fastest butterfly swimmers, the men who had finished first and second at the Asian Games two months ago.

Except that Singapore's Joseph Schooling did not even make the podium in the 100m fly final at the Singapore leg of the Fina Swimming World Cup last night.

The Olympic champion finished fourth at the OCBC Aquatic Centre, clocking 51.05 seconds.

The gold instead went to Chinese teenager Li Zhuhao (49.64) - who had been second to Schooling in the long-course event at the last two Asian Games.

Australian Matthew Temple (50.60) and Belarusian Yauhen Tsurkin (50.66) were second and third respectively,

Still, Schooling, who had been second overall in the heats yesterday morning in 50.97, behind Li (50.61), was determined to take the positives from his race.

"It's the first time that I've had to come all the way from the US and get up and race on such a short turnaround, and I've got to learn how to do that," said the 23-year-old, who congratulated Li with a hug after the race.

"The result wasn't what I wanted, but it's early in the season and it gives me something to work towards.

"I wish I could have gone faster, but that's just where I am right now body-wise, and that's OK."

He had returned from the United States, where he is an economics major at the University of Texas, Austin - only on Monday, and he is competing in the short-course Fina Swimming World Cup for the first time since 2008.

"I could see myself swimming at more World Cups when I'm back permanently but, overall, it was nice to see everyone come out here and I'll take the positives out of tonight," added Schooling, who paid tribute to the crowd of 1,030, saying their support proved the "highlight of (his) night".

Li, who finished second to South Africa's Chad le Clos in the 100m butterfly at last year's event here, was happy to have won the gold.

The 19-year-old said his time yesterday, a season-best effort, provided a welcome confidence boost ahead of next month's World Swimming Championships (25m) in Hangzhou.

But the teenager, who won the 100m fly title during the Beijing stop two weeks ago in 50.74, noted: "(Schooling) just came back from the US, and he could still be adjusting to different time zones and is not in his best form."

He and Schooling will clash again tomorrow, this time in the 50m fly. Li is also slated to compete in the 200m fly while Schooling will race in the 4x50m mixed medley relay.

Besides the surprise result in the men's 100m fly, there proved enough drama on the opening day of the three-day meet to keep the fans entertained.

In the first final of the evening, Dutchwoman Femke Heemskerk was in prime position to win the women's 400m freestyle, having finished top in the morning heats and leading throughout the final.

But a miscalculation saw her stop with a few laps to go and, although she scrambled to catch up, she eventually finished fourth while Germany's Reva Foos won the title.

A World Cup record was also set in the men's 50m freestyle, with Russia's Vladimir Morozov lowering his own record of 20.49sec by 0.01.

Morozov, the current series leader in the men's rankings, won the race in 20.48. He also won the 100m IM in 50.31sec, off his world record time of 50.26.

Meanwhile, women's series leader Sarah Sjostrom (57.49sec) edged out triple Olympic champion Hosszu (57.56) to win the women's 100m IM. The 25-year-old Sjostrom also won the 50m freestyle (23.21sec). Hosszu, a multiple world-record holder, later won the 200m fly in 2:02.86.

The meet concludes tomorrow.