Olympic Swimming:Michael Phelps no complacency, despite having broken records for fun London 2012, when claiming his 17th Olympic gold this evening, in the 100 metres butterfly.
On the eve of his retirement, Phelps provided an unforgettable reminder of his incredible talent and determination when he came from seventh at the turn to overpower his rivals and win in a time of 51.21 seconds.
South Africa's Chad le Clos, who beat Phelps in the 200 butterfly final, dead-heated for second with Russia's Evgeny Korotyshkin, but neither man could hold Phelps off once he started to roll his giant shoulders and kick.
By winning, he joined his American team mate Missy Franklin as the only triple gold medallists in London, after she broke the world record in the 200 backstroke final a few minutes earlier, and took his career tally to 21 medals.
He still has one more event to go before he hangs up his goggles, the 4x100 medley relay, an event the US men have never lost at an Olympics they have attended.
The US domination was the copperfastened soon afterwards when the 15-year-old Katie Ledeckyof the United States won the women's 800 metres freestyle gold medal.
Spain's Mireia Belmonte Garcia won silver, while Beijing champion Rebecca Adlington of Britain clinched bronze.
Teenager Franklinconfirmed her arrival as the new queen of the pool when she broke the 200m world record.
The 17-year-old from Colorado led the four-lap race from start to finish to win in a time of two minutes 04.06 seconds, slashing three-quarters of a second off Kirsty Coventry's world record, which was set in the now banned polyurethane bodysuit.
Russia's Anastasia Zueva won the silver medal and America's Elizabeth Beisel the bronze but neither could keep up with the bubbly Franklin, who opened up a body's length over the field after just 75 metres.
Franklin, who won the 200 backstroke world title last year, became the first woman in 12 years to complete the backstroke double at the Olympics and the first American since Melissa Belote in 1972.
France's Florent Manaudouwon the men's 50 metres freestyle gold ahead of Cullen Jones of the United Statesm, who took silver, and Brazil's Cesar Cielo.