<p>Tuesday's women's 100m backstroke final will be a battle of the record breakers with Australia's Kaylee McKeown going for gold against American Regan Smith and Canada's Kylie Masse.</p>.<p>The trio are the three fastest swimmers in the history of the event, all having held the world record, with McKeown the current owner.</p>.<p>They showed their form in Sunday's heats with Masse setting an Olympic record before Smith took it from her and then McKeown went even faster.</p>.<p>In the women's 100m breaststroke, American Lilly King faces a tough challenge to the defence of her title with South African Tatjana Schoenmaker in the prime lane four after qualifying fastest.</p>.<p>World record holder King's old Russian foe Yulia Efimova is also in the final.</p>.<p>The pair made headlines at Rio 2016, when King wagged her finger at the previously suspended Russian and branded her a drug cheat. That clearly still rankles Efimova.</p>.<p>"I'm rooting for Tatjana Schoenmaker," Efimova told Russian media. "If I don't win myself, then let Tatjana win."</p>.<p>The men's 100m backstroke features defending champion and world record holder Ryan Murphy of the United States going for a fourth career gold with Russian Kliment Kolesnikov looking dangerous and Australian Mitch Larkin also a threat.</p>.<p>The first final of the morning is the men's 200m freestyle with Britain's Duncan Scott and Tom Dean hoping to medal and American Kieran Smith in the lane between them.</p>
<p>Tuesday's women's 100m backstroke final will be a battle of the record breakers with Australia's Kaylee McKeown going for gold against American Regan Smith and Canada's Kylie Masse.</p>.<p>The trio are the three fastest swimmers in the history of the event, all having held the world record, with McKeown the current owner.</p>.<p>They showed their form in Sunday's heats with Masse setting an Olympic record before Smith took it from her and then McKeown went even faster.</p>.<p>In the women's 100m breaststroke, American Lilly King faces a tough challenge to the defence of her title with South African Tatjana Schoenmaker in the prime lane four after qualifying fastest.</p>.<p>World record holder King's old Russian foe Yulia Efimova is also in the final.</p>.<p>The pair made headlines at Rio 2016, when King wagged her finger at the previously suspended Russian and branded her a drug cheat. That clearly still rankles Efimova.</p>.<p>"I'm rooting for Tatjana Schoenmaker," Efimova told Russian media. "If I don't win myself, then let Tatjana win."</p>.<p>The men's 100m backstroke features defending champion and world record holder Ryan Murphy of the United States going for a fourth career gold with Russian Kliment Kolesnikov looking dangerous and Australian Mitch Larkin also a threat.</p>.<p>The first final of the morning is the men's 200m freestyle with Britain's Duncan Scott and Tom Dean hoping to medal and American Kieran Smith in the lane between them.</p>