Rio de Janeiro: Usain Bolt took the next step in his quest for a "triple triple" of sprint golds on Tuesday as American Christian Taylor and Croat Sandra Perkovic both retained their Olympic crowns.
Bolt, fresh from winning the 100m title for an unprecedented third time, safely came through the first round of his favoured event, the 200m.
Running in lane five of heat nine of 10, the 29-year-old coasted home in 20.28 seconds. American rivals Justin Gatlin and Lashawn Merritt also qualified for Wednesday's semi-finals, with the final slated for Thursday.
"It's a morning session and I'm not really a morning person. I just came out to qualify and that's what I did," said Bolt, praising the scheduling.
"I'm surprised it's so settled. Normally we have to do two rounds in one day. It's actually much better for the 200m so we have time to recover over the days.
"For me it's easy I've been doing it for years. You just celebrate on the night, just be happy and then you refocus the next day to go again."
The morning session's two medal events went the way of defending champions.
In the triple jump, Taylor set a season's best 17.86 metres with his first leap, good enough to beat compatriot Will Claye in a repeat of their one-two finish in London four years ago.
"The job is done," said Taylor. "Back to back, it's very special."
Claye celebrated his silver by proposing to long-time girlfriend, hurdler Queen Harrison.
"I woke up this morning and said today is going to be the best day of my life," he said. "It was stressful, man, because I didn't know if she was going to say yes or not."
The women's discus went the way of Perkovic, the Croat in imperious form as she dominated the competition, her best of 69.21m out-distancing France's Melina Robert Michon (66.73m) and world champion Denia Caballero of Cuba (65.34) by some way.
Elsewhere on the track, Ethiopia's newly-crowned 10,000m champion and world record holder Almaz Ayana moved closer to a distance double as she won her 5000m heat in 15:04.35 to progress to Friday's final.
Defending silver medallist and two-time former world champion Vivian Cheruiyot, silver medallist behind Ayana in the longer distance in Rio, Hellen Obiri and Mercy Cherono will make up a strong Kenyan contingent.
Algerian defending champion Taoufik Makhloufi overcame just two hours sleep after bagging silver in the 800m to advance from round one of the 1500m.
Makhloufi, who came in second in the 800m behind David Rudisha late Monday, timed 3min 47.07sec to win his heat.
"I had some massage after the 800m," he said.
"I was in my bed at 4 o'clock in the morning and I slept only two hours!
"This part between the 800m and the heats of the 1500m was always going to be the most difficult part in qualifying for the semi-finals of the latter."
Makhloufi's main rival will likely be Kenyan Asbel Kiprop, 2008 gold medallist and three-time defending world champion, who won his 1500m heat easily in 3:38.97.
Brazilian hopes of an Olympic pole vault double came to an abrupt end when home medal hope Fabiana Murer bombed out of the women's qualifying competition after failing to register a mark.
Rio's Olympic Stadium lit up Monday when Murer's teammate Thiago Braz Da Silva trumped Frenchman Renaud Lavillenie for gold in the men's competition with an Olympic record of 6.03m.
Murer, world silver medallist last year in Beijing, failed to live up to expectations however.
The 35-year-old skipped the three first entry marks of 4.15, 4.30 and 4.45m, coming in at 4.55m.
But she failed with her three attempts at the height, well below her personal best of 4.87m which she vaulted this season.
There was no such drama for current world and Olympic champion Jennifer Suhr of the United States, Cuba's defending Olympic silver medallist Yarisley Silva and European champion Ekaterini Stefanidi who all comfortably vaulted the qualifying mark of 4.60m.