When Michael Phelps walked into the press room at the Aquatics Centre on Saturday August 4, 2012, he left no-one in any doubt that his decision to retire was final.

Michael Phelps won the 17th Olympic gold medal of his career, and his 21st overall, when he produced a majestic performance in the 100m butterfly.

Michael Phelps' bid to win eight gold medals at the Beijing Olympics came within a fingertip of failure in the 100metres butterfly, his penultimate event at the Water Cube.

Michael Phelps moved to within a single victory of equalling Mark Spitz's hallowed Olympic gold medal-winning record as he destroyed the opposition once again to win the 200metres individual medley at Beijing's Water Cube.