Adam Peaty hopes to emulate retired American great Michael Phelps, the only swimmer to win gold in the same event at three successive Games, at the Paris Olympics.
Team Australia's Emma McKeon is the first woman swimmer to win 7 medals at a single Olympics.
Competing in their maiden Olympics, both swimmers put up underwhelming performances and were unable to match their personal best times in the 100 metres backstroke.
Ryan Murphy lost the second of his Rio backstroke titles to Russian Evgeny Rylov at the 2020 Olympics on Friday and the US swimmer then suggested doping had played a part in his demise as events took an acrimonious turn at the Tokyo pool.
Caeleb Dressel and Katie Ledecky added to the United States' gold medal haul at the Tokyo Olympics on Saturday while Australia's sensational run continued with Kaylee McKeown winning the 200m backstroke for their seventh gold in the pool.
Australia's Ariarne Titmus drew first blood in her Olympic showdown with American Katie Ledecky on Monday after her brilliantly timed swim secured a famous victory in the 400m freestyle at the Tokyo Games.
Chinese supporters have been visible and vocal.
Caeleb Dressel of the United States powered to victory in the men's 50m freestyle to claim his third individual gold medal at the Tokyo Games on Sunday, while Australia's Emma McKeon also completed the sprint double with victory in the women's 50m.
Caeleb Dressel won the blue riband men's 100m freestyle as the United States celebrated two gold medals in the Tokyo pool on Thursday while China's women responded with two golds, and a world record, of their own in another thrilling day of swimming.
Pint-sized 13-year-old Momiji Nishiya took gold in street skateboarding -- new to the Olympics in Tokyo -- while in one of the Games's staple sports a "Terminator" hunted down a dominator to set the swimming pool alight.