American Jessica Hardy kept the world records flowing at the world short-course championships with a sparkling victory in the women's 50 metres breaststroke on Thursday.
Hardy, who won the world long-course title in 2007, clocked 29.58 seconds to beat the 29.90 set by Australia's Jade Edmistone in Brisbane in 2004. It took the world record tally to four after three marks tumbled on Wednesday's opening night.
Kirsty Coventry, who broke the women's 400 individual medley world record on Wednesday, bagged her second title of the five-day championships with a championship record 57.10 seconds in the 100 backstroke.
Coventry, third at the 50-metre mark, edged out Ukraine's Kateryna Zubkova (57.15), with Croatia's Sanja Jovanovic third.
The US-based Zimbabwean was soon back in the water to win her 100 individual medley semi-final. "I'm getting a little tired...But I do that in training, so I think it's just making me mentally stronger," Coventry said.
Hardy seized control of the 50 breaststroke final from the start and finished more than half a second ahead of her nearest pursuer, Yuliya Efimova of Russia.
Efimova, who won the European 200 breaststroke title last month, clocked 30.22 but to no avail as she was disqualified for a false start.
Silver was shared by Britain's Kate Haywood and Australia's Sarah Katsoulis who both touched in 30.35. Edmistone finished fifth, losing the title she won in 2006 and the world record.
"I knew I felt good. I was hoping (for the world record) but I didn't expect it," Hardy said.
Ryan Lochte, a member of Wednesday's world record breaking American 4x100 freestyle relay squad, claimed his second Manchester gold with a fluent defence of his 400 individual medley title.
Lochte always looked in control and although fellow American Robert Margalis and Ioannis Drymonakos of Greece were in close contention as they moved on to the concluding freestyle leg, he collected the gold in four minutes 3.21 seconds.
Margalis, the 2003 Pan-American champion, took silver in 4:03.74 and Drymonakos, the European silver medallist, bronze in 4:05.11.
But Lochte and Margalis were denied medals in the 4x200 freestyle relay in which Australia edged out Britain, with Italy third and the U.S. fourth.
Britain's Rebecca Adlington came close to breaking the women's 800 freestyle world record, tantalisingly falling off the pace in the last 50 to clock a championship record 8:08.25, 0.25 seconds outside American Kate Ziegler's world mark.
"Didn't have a clue I was that close. I never expected to go that quick," she said after winning by more than four seconds from Australia's Kylie Palmer and Spain's Erika Villaecija.
Liam Tancock had earlier brought the British hosts their first title of the meet with a bold victory in the 100 backstroke, turning at the 50 inside world record pace and scoring a clearcut win in 50.14 ahead of American 2001 world long-course champion Randall Bal (50.42).
Petr Mankoc put Slovenia on the top step of the podium, claiming gold in the 100 butterfly by half a second from 32-year-old Australian father of two Adam Pine in a championship record 50.04.
Ukraine's Igor Borysik also clocked a championship record in winning the 100 breaststroke in 57.74, from South Africa's Cameron Van Der Burgh and fellow Ukrainian Oleg Lisogor.