RIO DE JANEIRO - On the podium in Rio, the butterfly men stand. Three silver medallists, Michael Phelps, Chad le Clos, Laszlo Cseh, together on one level. Joseph Schooling alone and higher. He is only just discovering that it is beautifully lonely at the top. The bronze medallist's spot is empty, just open space, like what there is behind Schooling at the finish of the Olympic 100m butterfly final.

In 2004 at Athens, the gap between first place and second is .04 of a second; in 2008 it is .01, in 2012 it is .23, here it is a massive .75. At the mixed zone, le Clos will sum up Schooling's time of 50.39 seconds in two admiring words, "crazy quick".

This kid - he's 21, Phelps 31, Cseh 30, le Clos 24 - has style. He doesn't just win his first final, he ends a 100m race after 60 metres. "After the turn and three strokes no one was going to catch him," says Sergio Lopez, the coach who made him. This kid - face like a boy, ambition like a streetfighter - has panache. He grows up worshipping a water god who hasn't lost a major 100m butterfly race since 2005 and then he drowns his deity's dream.

In Greek mythology, Nereus was the old man of the sea. His father was the Sea, his mother the Earth. In modern times his equivalent is Phelps, 31, the great old man of the pool. He lives on Land, he ruled the Water. He's won more individual golds than Leonidas of Rhodes did at the Ancient Olympics in 152 BC and hasn't lost a race all week in August 2016.

Till a boy born in Bedok, who starts swimming and dreaming because of Phelps, will eventually out-swim Phelps. What conviction, what cheek, what courage.

Phelps and Schooling meet on the pool deck like ancient duellists at just after 10pm in Rio: American in black cloak, Singaporean in red. The crowd rises for Phelps, later they will stand for Schooling. Up in the stands, May Schooling is nervous. A Dutch spectator hears she is the mother of the challenger and produces his vuvuzela from a bag and blows it. The swimmers are off.

Joseph swims, May pleads. Anxiety has reduced her to her usual one-word race vocabulary: "Go, go, go, go, go." Joseph's a good son, he listens to his mother. Go, he does. The race is not making sense: By the end you expect Phelps, even if tired, to go faster except Schooling will not go slower. He hits the wall first and May manages to find another word - "ecstatic". A Singapore flag waves in her hand and a phone, which she's too scared to open, is buzzing wildly in her hand. A stranger asks, "the mama?" and takes a wefie with her.

All those years she travelled to America when Joseph was in school there, cooking, caring, believing, trusting, doing all that invisible stuff that parents do, and now look at what her boy has gone and done? In 50 seconds he's changed her world, his world, our world. Every Singaporean looks a little dazed as if they've seen a miracle and are unsure if it's real.

Downstairs, Quah Zheng Wen, the talented butterflier stands quietly. "It's pretty amazing seeing our flag out there. It's something else. I'm proud about how far we have come, especially Joe." Standing a few feet from him is Lopez, in Singaporean red, a bulky, heavy man, who looks like he's escaped from a wrestling ring, and now he is crying. Muscle gone to mush.

This Schooling, he's shaking everyone's world. This Schooling, for this night, it is his world. Three of the greatest butterfliers, all older, are paying homage to him. "I'm proud of Joe," says Phelps and because he's a competitor, the ultimate racer, he'll like it that Schooling didn't confuse respect with mercy during the race. Perhaps in sport the greatest compliment to your idol is to beat him and thus show him how fully you have been inspired.

Phelps, who comes in late for the press conference, is generous. He tells reporters who hurl questions at him, hey, the "kid just won a gold, ask him some questions". He says he's "excited to see how much faster (Schooling) goes". Schooling in return is deferential and humble: "One gold medal is nuts, I can't imagine 22 or 23."

This is the loveliest moment of the night. It's even sweet. The kid courteous, the king classy. You can't say a baton has been passed because Phelps' 22-gold baton should be kept in a museum. But a calendar is changing. It's finally now 2016 AP. After Phelps.

Phelps dared Schooling to dream and he did and now Schooling dares us. He, and his parents, and coach, have demonstrated what is possible if you take risks, show commitment, make an investment, and keep the faith. We would have been happy with any colour of medal, but he only wanted gold. Now proof of his unwavering belief and labour is hanging from a ribbon round his neck.

Schooling worked all his life for gold, but wearing gold is not easy. It's almost unnerving to be an Olympic champion, it's dazzling, it's difficult to digest that you're the best in the world. But if he needs a mentor he can always call the retiring Phelps.

Fittingly, an evening that began on the pool deck with the American and Singaporean, ended the same way. Medals awarded, both men walked past adoring crowds and clicking cameramen, lost in amiable chatter. Schooling is not quite Phelps' equal and yet on this night he was his conqueror. The 100m butterfly was over and they walked together into new lives: one the greatest champion, the other the latest.