Lithuanian breaststroke specialist Ruta Meilutyte on Monday became the first swimmer to break a world record at the 15th FINA World Championships as she won the 100 metres in one minute 04.35 seconds.
The time the 16-year-old Olympic champion swam in the semifinals in the Palau Sant Jordi pool in Barcelona on Monday was 0.10 of a second faster than American Jessica Hardy's record from 2009. Meilutyte had already broken the championship record in the heats.
There was disappointment for the strong US team in the medal races as it failed to pick up gold.
Sweden's Sarah Sjostrom and Australian Christian Sprenger won the women's and men's 100m breaststroke, while Brazilian Cesar Cielo continued his domination of the sprints with gold in the 50m butterfly.
The final gold medal of the day went to Katinka Hosszu in the women's 200m individual medley. The Hungarian won in 2:07.92, with silver going to Australian Alicia Coutts, who had earlier also won silver in the 100m breaststroke. China's Olympic champion Ye Shiwen surprisingly finished outside the medals as she came in fourth, more than a second behind Belmonte.
Cielo speeds away
In the 50m butterfly, Cielo showed that he continues to be the best sprinter in the world as he won in 23.01, beating American Eugene Godsoe from the United States by 23.05. Bronze went to France's Frederick Bousquet in 23.11.
In the two opening races Sjostrom and Springer came close to breaking world records, but fell just short. Australian Sprenger was lying third at the turn in the 100m breaststroke, with leader Cameron van der Burgh well below the world record split, but as the South African fell behind on the final metres, Sprenger touched just before him.
The Australian won gold in 58.79, 0.18 seconds ahead of Olympic champion and world record holder van der Burgh.
In the women's 100m butterfly the 2009 champion Sjoestrom was lying second at the turn behind Dane Jeanette Ottesen Gray, whose time of 26.06 was 0.33 below the world record split.
Ottesen Gray faded on the second leg though and first had to allow Sjostrom, who finished in 56.53, Coutts, who took silver in 56.97 and bronze medal winner Dana Vollmer past.
The results: Men: 100m breaststroke: 1. Christian Sprenger (Aus) 58.79s, 2. Cameron van der Burgh (RSA) 58.97, 3. Felipe Lima (Bra) 59.65; 50m butterfly: 1. Cesar Cielo (Bra) 23.01, 2. Eugene Godsoe (USA) 23.05, 3. Frederick Bousquet (Fra) 23.11.
Women: 100m butterfly: 1. Sarah Sjoestroem (Swe) 56.53s, 2. Alicia Coutts (Aus) 56.97, 3. Dana Grant (USA) 57.24; 200m Individual Medley: 1. Katinka Hosszu (Hun) 2:07.92 2. Alicia Coutts (Aus) 2:09.39 3. Mireia Belmonte (Esp) 2:09.45.