Hosts China were the dominant force on the opening day of the International Swimming Federation Champions Swim Series event in Shenzhen, winning five of the 15 gold medals up for grabs.
Among the home nation's quintet of victors was Liu Yaxin, who came out on top in the women's 200 metres backstroke at the Shenzhen Universiade Center Swimming Natatorium.
The 20-year-old finished in a time of 2 min 10.34sec, beating Hungary's Katinka Hosszú, the Rio 2016 Olympic silver medallist, by 1.78 seconds.
The Netherlands' Kira Toussaint was a further 0.66 seconds behind in third place.
There was also success for China in the women's 200m breaststroke, which saw Yu Jingyao claim victory in 2:24.64.
Compatriot Ye Shiwen was the runner-up in 2:26.03, while Italy's Martina Carraro rounded off the podium in 2:27.59.
Completing China's list of winners today were two-time reigning world champion Xu Jiayu in the men's 100m backstroke, Wang Shun in the men's 200m individual medley and world record holder Liu Xiang in the women's 50m backstroke.
Xu triumphed in a time of 53.01, followed in the standings by the United States' Matt Grevers in 53.54 and Canada's Markus Thormeyer in 54.54.
Wang also held off American opposition to win in 1:57.76, with Michael Andrew second in 2:01.78 and Josh Prenot third with 2:01.89.
As for Liu, she touched home in 27.36 and was joined in the top three by Toussaint, in 28.07, and Austria's Caroline Pilhatsch, in 28.19.
The only other two nations to secure multiple gold medals today were Hungary and Italy, with two each.
Hungary's winners were Tamás Kenderesi in the men's 200m butterfly and Ajna Késely in the women's 400m freestyle.
Kenderesi prevailed in 1:55.17, ahead of Japan's Masato Sakai in 1:56.73 and Ukrainian Denys Kesyl in 1:57.82.
Késely, meanwhile, led a Hungarian one-two finish ahead of Boglárka Kapás, clocking 4:09.05 to her compatriot's time of 4:09.64.
Russian Anna Egorova took the bronze medal in 4:12.18
Italy's gold medallists were Elena Di Liddo in the women's 100m butterfly and Carraro in the women's 50m breaststroke.
Di Liddo's winning time was 58.37, with Denmark’s Jeanette Ottesen the runner-up in 58.75 and The Netherlands' Ranomi Kromowidjojo completing the podium in 59.99.
Carraro beat the American Molly Hannis to first place by 0.11 seconds, in a time of 30.38, and third spot was occupied by Jamaica's Alia Atkinson in 30.63.
There were also victories for Russia’s Vladimir Morozov in the men's 50m freestyle in 21.70, Brazil's Nicholas Santos in the men's 50m butterfly in 23.28, Hong Kong’s Siobhan Haughey in the women's 100m freestyle in 53.47, The Netherlands' Arno Kamminga in the men's 100m breaststroke in 58.61, and Lithuania’s Danas Rapšys in the men's 200m freestyle in 1:46.50.
In the mixed 4x100m freestyle relay, the team made up of Kromowidjojo, Haughey, the US' Jacob Pebley and Ukraine's Andrii Govorov, the men's 50m butterfly silver medallist, clinched first place in 3:28.40.
Action in Shenzhen concludes tomorrow, with a further 15 races.