Lithuania's teenage Olympic champion Ruta Meilutyte broke the women's 100m breaststroke world record with a new mark of 1min 04.35secs on Monday in the semi-finals at the swimming world championships.
The 16-year-old, who pulled off a shock win in the Olympic final in London last year, blazed into Tuesday's final in Barcelona and punched the water repeatedly with delight when her record was confirmed.
She broke the four-year-old mark of 1min 04.45secs, set by Jessica Hardy of the USA during the era when the high-tech swim suits were legal and the petite Lithuanian burst into tears as her achievement sank in.
Meilutyte, who trains in Plymouth, England, is the hot favourite in both the 50m and 100m breaststroke in Barcelona, an unusual position for the blonde schoolgirl, who was little known outside swimming circles just a year ago.
Meilutyte was voted best Lithuanian athlete of 2012 in her home country after her Olympic triumph.
The Lithuanian sent warning signals to opponents in June when she became the first woman to go under 30 seconds in the 50m breaststroke in a textile suit with a European record of 29.96 sec.
Last month, she also beat her own European record in the 100m breaststroke with 1min 05.20 sec before she tore up the world record in Barcelona.