VIDEO: Take a dip with Chad le Clos
GALLERY: Le Clos's golden moment
Phelps was leading le Clos by 0.58 seconds at the last turn, but le Clos managed to overtake Phelps with his last few strokes.
The South African said that he has always admired Phelps. "Ever since 2004 when he won six gold medals, he has been an inspiration and role model," le Clos said.
"I have all his major races on my computer, I think I have watched the 100m butterfly Beijing final, when he beat Cavic by 0.01 seconds, a million times. I have it in seven different languages."
He said that he studied the races and learned from them. "Watching all Michael's races I know he finishes strong. It sounds crazy but I actually thought I was Michael at the last turn," le Clos said.
"When I turned I looked at him and there was a trigger point I just thought I could try do something special. The last 25 metres came in slow-mo and I just remember thinking to myself and my coach saying 'keep it long and make sure you don't shorten up.'"
Le Clos just managed to touch the pad before Phelps, but the South African said he did not really know how he did it. "To be honest, I think I am a bit lucky."