Irvine, USA: Kathleen Baker set a world record of 58.00sec Saturday to win the 100m backstroke at the US swimming championships.
Baker, silver medalist in the event at the 2016 Rio Olympics, improved on the world record of 58.10 set by Canadian Kylie Masse at the World Championships in Budapest on July 25 of last year.
Baker, who tied for first with Regan Smith in the 200m backstroke this week, clocked a blistering 27.90sec over the first 50m and held on for the victory.
She notched the first world record of the championships, the selection meeting for next month's Pan Pacific Championships in Tokyo. The two meets together are the qualifiers for the World Championships in South Korea next year.
The top three finishers all broke 59 seconds, with Olivia Smoliga second in 58.75 and Smith third in 58.83.