Japan's Tokyo Olympic 400-meter individual medley gold medalist Yui Ohashi kept her hopes of an IM double alive when she won through to the women's 200 IM final on Tuesday.

She finished third in her heat at Tokyo Aquatics Centre in a time of 2 minutes, 9.79 seconds, the fifth-fastest time overall and 0.58 second behind top qualifier Kate Douglass of the United States.

"I swam well for a morning race. I'm feeling confident because I won the 400 IM. I'm hoping to be daring (in Wednesday's final), brushing aside fear of failure and aiming for things like a personal best," said Ohashi.

Yui Ohashi of Japan competes in the women's 200-meter individual medley semifinals at the Tokyo Olympics on July 27, 2021, at Tokyo Aquatics Centre. (Kyodo)(SELECTION) ==Kyodo

In the men's 200 butterfly semifinals, Daiya Seto's horror Olympics continued, the Japanese finishing seventh in his heat and missing the final with the 11th fastest time overall. Tomoru Honda will carry Japan's hopes in the final after qualifying with the eighth-best time.

"I couldn't swim well. I wanted to get good results but the tide is really working against me," Seto said.

After entering the games with expectations of multiple medals, Seto now has just one more chance to make his first final of the games when he swims the 200 IM heats on Wednesday.

"I hope I can swim a satisfying race in the 200 IM. I have at most three more races in the Olympics. Every single one counts," he said.

Australian Kaylee McKeown provided the highlight swim of Tuesday morning's finals, the 20-year-old adding an Olympic record to her world record in the women's 100 backstroke. She clocked 57.47 seconds to head Canada's Kylie Masse and Regan Smith of the United States.

Yui Ohashi of Japan competes in the women's 200-meter individual medley semifinals at the Tokyo Olympics on July 27, 2021, at Tokyo Aquatics Centre. (Kyodo)(SELECTION) ==Kyodo

My legs were definitely hurting in the last 20m...but I have trained for that and I knew I had a really strong back-end and a really good chance to be on the podium," McKeown said.

In the men's 100 backstroke, Russian athletes went one-two, Evgeny Rylov setting a new European record of 51.98 seconds when he touched out his countryman Kliment Kolesnikov by 0.02 second. American Ryan Murphy took bronze.

Britain also snagged a tight one-two result, its coming in the men's 200 freestyle, when Tom Dean beat Duncan Scott by 0.04 second. Fernando Scheffer of Brazil claimed the third step of the podium.

In the last final of the morning session, Lydia Jacoby got the United States its first gold of the day in the pool, beating Tatjana Schoenmaker and Lilly King in the women's 100 breaststroke.