Wins for Phelps and Ledecky - London 2012 - Swimming
Michael Phelps marked the final individual swim of his career with victory in the 100m Butterfly, while 15-year-old Katie Ledecky won the 800m Freestyle on her senior international debut.
Phelps clinched his 17th Olympic gold medal, and 21st medal overall, when he came from seventh at the halfway point to win in 51.21 ahead of Chad le Clos, his conqueror in the 200m, and Evgeny Korotyshkin, who shared second place.
It was the final individual race of the 27-year-old's career, with just the 4 x 100m Medley Relay to come before the Baltimore swimmer bows out of competition.
He said: 'I am just happy that the last one was a win, that is all I wanted coming into tonight.'
Meanwhile, Ledecky led from start to finish and was under world record pace until the final few metres as she touched in 8:14.63, the second fastest time in history behind Rebecca Adlington's world record from Beijing 2008.
Mireia Belmonte Garcia was 4.14secs adrift in second, with Adlington securing her second bronze of the week in third.