The athletics has already been startled by a world record in the women’s 10,000 metre for Ethiopia’s Almaz Ayana.
Schooling, 21, strayed from the script that had laid out 31-year-old Phelps would get a 23rd career gold medal and fifth of the week in the 100 metres butterfly.
Phelps, who gets one more chance to extend his all-time record medal tally in the 4x100m medley relay on Saturday, was relegated to a three-way dead heat for silver with South African Chad le Clos and Hungary’s Laszlo Cseh. He called the result “kind of cool.”
Schooling, who was inspired to become a top-level swimmer by a meeting with Phelps as a 13-year-old, said the night had been “just crazy.” He set an Olympic record of 50.38sec.
“He said ‘good job, that was a great race’,” Schooling told of Phelps’s reaction. “I told him to go four more years and he said ‘No way.'”
Another new generation swimmer, Katie Ledecky, completed the first 200m, 400m and 800m freestyle treble since 1968 — and with a world record.
America’s latest swimming sensation won the 800m in 8min 04.79sec, inside her seven-month old record of 8:06.68.
Phelps has insisted there is no way he is changing his mind about quitting after his fifth Olympics. And Jamaican hero Bolt has said he will also give up after these Games.
The 29-year-old world record holder will start the 100m heats on Saturday in preparation for a predicted showdown with US rival Justin Gatlin in the Olympic stadium on Sunday.
Bolt’s script aims for a third treble of the 100m, 200m and 4x100m relay golds.
While Bolt’s superstar status is unblemished, Gatlin, the world’s fastest man this year, is still seeking to redeem his name after two doping bans.
Eyebrows were raised about the way in which Ethiopia’s Ayana smashed the 23-year-old women’s 10,000m record by nearly 14 seconds with a time of 29min 17.45sec.
“I praise the lord, the lord gives me everything,” she said through an interpreter when asked about the performance. “My doping is my training, my doping is Jesus — otherwise I’m crystal clear.”
Athletics is battling a torrent of doping controversies after world body the IAAF suspended Russia’s track and field team.
Michelle Carter of the United States stunned defending champion Valerie Adams of New Zealand with her very last throw to win the gold medal in the women’s shot put.
Wang Zhen of China won the men’s 20km race walk gold, 15 seconds ahead of compatriot Cai Zelin.
Britain’s Jessica Ennis-Hill leads Belgium’s Nafissatou Thiam by 72 points in her bid to retain the heptathlon title. She won the 100m hurdles, finished third in the high jump and second in the shot put and 200m.
Elsewhere, cyclist Bradley Wiggins became Britain’s most decorated Olympian of all time and Rafael Nadal, returning from a wrist injury, won men’s doubles gold.
Wiggins, along with Edward Clancy, Steven Burke and Owain Doull beat Australia in a world-record time to win the men’s team pursuit at the Rio velodrome. It was Wiggins’s eighth medal, the most compiled by a Briton.
Nadal paired with Marc Lopez to win the men’s doubles 6-2, 3-6, 6-4 against Romania’s Florin Mergea and Horia Tecau, sealing his second gold medal after winning the singles in 2008.
French giant Teddy Riner, who stands 6ft 8in (2.04 metre) and weighs more than 300 pounds, won the men’s +100kg judo by penalties from Japan’s Hisayoshi Harasawa.
Egyptian judoka Islam El Shehaby was jeered after refusing to shake hands with his Israeli opponent at the end of their heavyweight first round encounter. He had to appear before an IOC ethics commission.
In football, American goalkeeper Hope Solo lashed out at Sweden as “cowards,” as the 2004, 2008 and 2012 women’s gold medallists and reigning world champions went out 4-3 on penalties in the quarter-finals.
“We played a bunch of cowards,” Solo told Sports Illustrated. “The better team did not win today.”