Quadruple Olympic champion Missy Franklin of the US powered to her third gold at swimming's world championships with victory in the women's 200m freestyle final on Wednesday.

Franklin, 18, claimed her third title in Barcelona when she touched the wall in a personal best of 1 min, 54.81 sec with Italy's Federica Pellegrini taking silver at 0.33 sec back and France's Camille Muffat claiming bronze 0.91 sec adrift.

"I'm extremely happy. That was my first PB of the meet and my first time under one minute, 55, so I'm excited," said Franklin.