The 13th and final American gold came in the women's 4x100 metres medley, with 17-year-old Regan Smith breaking the 100m backstroke world record during the first leg.

Smith swam the opening section in 57.57secs to set the US on the way to victory.

Smith, Lilly King, Kelsi Dahlia and Simone Manuel won the race in a record 3 minutes 50.40secs, more than three seconds ahead of runners-up Australia, while Canada were third in 3:53.58.

Manuel and King both won two golds today (July 28) after victories in the 50m freestyle and breaststroke, respectively, increasing to three and four their personal gold tallies.

Manuel caused an upset in the freestyle when she defeated world record holder Sarah Sjöström from Sweden.

The American, who won the 100m earlier in the meeting, won by just 0.02 as she swam a time of 24.05.

Cate Campbell of Australia took bronze in 24.11 and Denmark's Pernille Blume was fourth despite being just 0.01 slower than Campbell and 0.07 slower than Manuel.

King won the 50m breaststroke in 29.84, ahead of Italy's Benedetta Pilato in 30.00 exactly, while Yuliya Efimova was third, the Russian swimming 30.15.

Britain won the men's 4x100m medley in a European record of 3:28.10, just 0.35 ahead of the United States with Russia third in 3:28.81.

Adam Peaty claimed his third gold of the Championships and his fourth medal overall, alongside team mates James Guy, Luke Greenbank and Duncan Scott.

Elsewhere, Hungarian Katinka Hosszu delivered again in the women’s 400m individual medley, taking her fifth World Championships gold medal in this discipline.

She won in 4:30.39, with China's Shiwen Ye second in 4:23.07 and Yui Ohashi of Japan third in 4:32.33.

Daiya Seto, Japanese swimming's poster boy ahead of the Tokyo 2020 Olympics, laid down a marker ahead of next summer with victory in the men's 400m individual medley.

Seto won in 4:08.95, with American Jay Litherland taking silver in 4:09.22 and Lewis Clareburt from New Zealand earning bronze in 4:12.07.

Two-times men's 1,500m champion Gregorio Paltrinieri of Italy was beaten by Germany’s Florian Wellbrock, who added gold to his 10k open water title in Gwangju. 

Wellbrock won in 14:36.54, Mykhailo Romanchuk of Ukraine took silver in 14:37.63 and Paltrinieri the bronze in 14:38.75.

The opening final of the night saw a surprise, as Zane Waddell won the 50m backstroke from lane two.

The South African swam 24.43, edging out Evgeny Rylov of Russia into second place by 0.06.

Another Russian, Kliment Kolesnikov, swam 24.51 for bronze, less than a 10th of a second ahead of American duo Ryan Murphy and Michael Andrew.