Though Danas Rapsys spent "all night" thinking about what could have been his first long-course world title after being disqualified from the men's 200m freestyle at last month's world championships, he appears to have moved on well.

Yesterday, the Lithuanian won the 400m free at the Fina Swimming World Cup Singapore, after also clinching the title in World Cup record times at the first two stops in Tokyo and Jinan.

At the world meet in South Korea, Rapsys had appeared to touch the wall first in the 200m free final but he was disqualified for moving on the blocks.

China's Sun Yang, who competed under a doping cloud, was crowned champion instead. Joint-bronze winner Duncan Scott of Britain refused to shake Sun's hand or pose for photos with him after the medal ceremony. It was the second podium protest of the meet against the Chinese after Australian Mack Horton's in the 400m free.

Rapsys claimed he was not aware of the furore that followed his disqualification, saying: "I don't know what happened, I don't want to hear anything about it, so I just went home to rest.

"I was thinking about (it) all night, but it happens... I need to keep going stronger. Everything is in the mind, so I need to keep training and working hard."

The 24-year-old believes there are more improvements to be made after his 3min 45.59sec effort in the 400m free at the OCBC Aquatic Centre. "I made a little change but it didn't work. The new tactic (was) to start a little bit slow and then finish stronger," he added, describing his time as "a little bit bad".

Still, he could be excused for that, with his coach Ina Paipeliene hospitalised for the past two days with chest pains.

Rapsys, the short-course world champion in the event, has done well at the Fina World Cup series.

He also won the 200m free at the previous two legs in Cup-record times and is on the right track for the Olympic Games next year. But he would only say: "I need to do my best. Who knows what will happen in Tokyo, so I need to work hard."

Another swimmer who intends to continue working hard is Quah Jing Wen. She lowered her 200m butterfly Singapore mark for the second time in two weeks, her 2:10.26 effort bettering the 2:11.38 set at the Tokyo leg on Aug 2.

She was third behind Hungarians Katinka Hosszu (2:07.07) and Zsuzsanna Jakabos (2:07.48).

Quah, who had not been expecting to clock a new best so soon, said: "I feel like that time has been waiting for me to reach it. I would have like to have gone under 2:10 but going 2:10, with my best time being 2:12.01 only a month ago, it's an amazing feeling."

The 18-year-old, who leaves next week to start her third year of university at Texas A&M, said she has been doing a lot of aerobic training in the United States to try and improve her speed in the final 100m.

She added: "Just now, I was able to apply what I've been doing in training a lot better, and that makes me happy. I'm going to continue what I'm doing and work on more of my back-end speed."

She is not the only one who posted a new personal best on the first day of the three-day meet.

Vladimir Morozov, last year's overall series winner, set a Cup record of 21.27sec to finish first in the men's 50m freestyle.

The Russian, still in disbelief after his race, said: "It's my best time in six years, I'm very happy. I couldn't believe it, I was thinking maybe 21.4 or 21.5, that's what I did at the first two World Cups but not 21.2.

"I still have to process it."

Nicole Chia