Shaunae Miller praised God after diving over the line to win the women's 400m gold by 0.07 seconds.
The Bahamian athlete pipped the American world champion Allyson Felix in a thrilling finish. After leading the field into the home straight Miller's legs appeared to fail in the final metres and Felix looked like she would overtake.
But Miller threw herself across the line to win gold in a time of 49.44 seconds.
After the race Miller told BBC Sport: "I just give God the thanks and praise. He has bought me so far.
"It is such an emotional moment for me but I just give God the thanks and praise."
Of her dive to the line Miller, 22, said: "The only thing I was thinking was the gold medal and the next thing I know I was on the ground.
"It was just a reaction."
Miller, who was her country's flag bearer in the games' opening ceremony, said that during her victory lap she "just remembered all the hard workouts I have been doing. But like I said I just give God all the thanks and praise.
"I could not have done it without him. I am so happy and so grateful."
Some US fans questioned the legitimacy of Miller's move but Olympic champion and former 400m world record holder Michael Johnson said the dive was to "recover from falling". He tweeted: "Sprinters know the quickest way across the line is a well timed lean. Trust me on that."
Nevertheless some on social media could not resist some suggestions of a change of discipline.
Shaunae Miller was a little short of vertical, had good height off the board & had little splash, Gold medal diving performance #Rio2016— JaiRich (@JaiRich) August 16, 2016