Trayvon Bromell, the favourite to succeed Usain Bolt as men's 100 metres Olympic champion, just scraped into the second round as one of the fastest losers on Saturday.
The 26-year-old American was caught napping in his heat and finished fourth in the race won by Nigeria's Enoch Adegoke.
Bromell -- who ended the 2016 Olympics writhing in agony after tearing his Achilles tendon in the 4x100m relay final -- faced an anxious wait through the next heats before being confirmed as a faster loser with his modest time of 10.05sec.
"Shoot," said Bromell. "I was calm. Honestly, I have no words for it.
"It don't look like I actually pushed myself and that is going to be the thing my coach is mad about."
Bromell headed to see his coach while team-mates Fred Kerly and Ronnie Baker qualified easily from their heats.
Baker, at 27 appearing in his first Olympics but and better known for his exploits indoors over 60m, won his heat in 10.03sec.
"It felt easy. I look back at the screen after the race, and just honestly felt like a stroll, a casual stroll," said Baker.
"Tomorrow (Sunday), obviously, got to just turn it up a little bit. So this is just to get the nerves out, get my feet under me."
In an event lacking the quality of previous Games and with no sprinter yet to threaten to dominate as Bolt did, it might finally be Andre de Grasse's moment.
The 26-year-old Canadian, who has five minor individual medals to his name at world and Olympic games combined, posted the fastest time in the heats of 9.91sec.
He tried to brush off the expectation.
"I feel like people put it on me, but I enjoy it," said De Grasse.
"I have fun with it. It just makes me feel better, that I am one of the guys that can bring home a medal to Canada.
"It is my second Olympic Games and I am enjoying the moment."
Bolt's retirement pretty much brought down the curtain on a golden age for male Jamaican sprinters.
However, one keeps on hanging in there as a faded memory of the one mighty generation -- Yohan Blake.
The 31-year-old 2011 world champion in the 100m and silver medalist in both the 100 and 200m at the 2012 Olympics timed 10.06 sec in finishing second in his heat.
Blake, though, is talking up his prospects of keeping the Jamaican flag flying in the 100m.
"A little bit rusty," he said of his performance.
"First run, get the cobwebs out. I don’t feel too bad at all and I know I am in great shape so I am not worried.
"But I will come back tomorrow and do what I have to do."