Germany's Paul Biedermann received a boost ahead of his head-to-head with US demon Michael Phelps by breaking the world record in the men's shortcourse 400m freestyle.
The 23-year-old German clocked 3 minutes 32.77 seconds, nearly two seconds faster than Australian Grant Hackett's previous mark, despite only getting the green light to race on Friday after recovering from a thigh injury.
Biedermann and Phelps will compete Sunday in the 400m final.
Australia's Leisel Jones broke her own world record in the women's shortcourse 100m breaststroke.
The 24-year-old clocked 1 minute 3.00 seconds, beating her own mark of 1 minute 3.72 seconds, which she set six months ago in Canberra.
Japanese teenager Shiho Sakai broke the world record in the women's 200m backstroke to win the final in a time of 2 minutes 0.18 seconds, shaving 0.73 seconds off the previous mark set by Zimbabwe's Kirsty Coventry.
And South Africa's Cameron Van Der Burgh broke his own world record in the men's shortcourse 50m breaststroke, clocking 25.25 seconds to beat the record he set last August in Pietermaritzburg, South Africa.