Michael Phelps insists retirement decision is final after settling for silver

Michael Phelps was adamant there would be no retirement U-turn this time as he was beaten to gold by a Singaporean who used to idolise him.

Phelps missed out on a 23rd Olympic gold medal by finishing in a three-way tie for second in the 100 metres butterfly, but has one final opportunity in the 4x100m medley relay on Saturday.