Michael Phelps wins his third gold of the world swimming championships . Phelps wins 100 m butterfly but admits he is short of peak fitness . Swimming superstar Phelps has a record 25 world titles . It 's a tough race , '' Phelps told AFP . Mexico 's Cesar Cielo wins 50 m free for his second gold in Shanghai .
Michael Phelps wins his third gold of the world swimming championships . Phelps wins 100 m butterfly but admits he is short of peak fitness . Swimming superstar Phelps has a record 25 world titles . Mexico 's Cesar Cielo wins 50 m free for his second gold in Shanghai .