World champion Qin Haiyang swam the 10th fastest 50m breaststroke ever on Friday in the Asian Games heats, as Zhang Yufei set the 50m butterfly pace in her bid for a sixth gold medal.
China's Qin has been the dominant male swimmer in Hangzhou and is bidding to match his unprecedented world championship exploits and complete a sweep of the breaststroke titles.
With the 100 and 200m already won, he blitzed through his 50m heat in a searing 26.25sec, a new Games record and just outside the 26.20 that won him the world title at Fukuoka in July.
It was the second best of his career and the 10th quickest in history, with only British great Adam Peaty, who owns eight of the top 10 and the 25.95 world record, surpassing it.
"I had a great time because I have already been here once in May (for the national championships) and I am very satisfied with the arena," he said. "Everything's pretty good."
Teammate Sun Jiajun, who won bronze at the world championships, trailed him in 27.01.
While Qin has been a standout, Olympic and world champion Zhang is the competition's top gold medallist, winning the 100 and 200m butterfly, 50m freestyle and two relays.
She is red-hot favourite to add another in the 50 fly after her silver-medal performance behind Swedish world-record holder Sarah Sjostrom in Fukuoka.
Zhang cruised through her heat in 25.78 to qualify fastest ahead of teammate Yu Yiting (25.85) and Japan's defending champion Rikako Ikee (26.22).
She may even try for a seventh gold in the 4x100m medley relay, with the lineups for the final yet to be announced.
China's Li Bingjie has also had an outstanding Games, with four gold and a silver. She will be bidding to complete the 400-800-1500m freestyle treble in the 800 on Friday evening.
On the sixth and final day of action in the pool, China top the swimming medals table with 24 gold among their overall total of 49.
At the last Asiad, in Indonesia, Japan tied them at the top on 19 gold. But it has been a different story in Hangzhou.
They have won just three times, with South Korea picking up some of the slack, bagging five gold so far.
Kim Woo-min could add another in the 400m freestyle after winning over 800m.
He comfortably qualified first in 3:49.20, ahead of Malaysia's Khiew Hoe Yean (3:51.31), with Chinese pair Pan Zhanle and Zhang Ziyang also making the grade.
Olympic silver medallist Tomoru Honda should secure gold for Japan in the 200m butterfly, storming through his heat in a new Games record 1:53.30, the third fastest of 2023.
China's defending champion Xu Jiayu touched third into the 200m butterfly final as he seeks the backstroke treble, behind Japan's Hidekazu Takehara (1:59.78) and South Korea's Lee Ju-ho.