Brazilian icon Neymar entered the record books with the fastest goal in Olympic football history as Usain Bolt prepared to take another step closer to triple gold immortality.
As Rio was hit by more embarrassment which saw the arrest of veteran sports administrator Patrick Hickey, it was left to the Games marquee names to right the ship.
Controversial South African runner Caster Semenya entered the track and field fray while British long distance star Mo Farah recovered from a worrying slip to reach the 5,000m final.
It was also a red-letter day for golf as a women's tournament teed-off for for the first time in 116 years.
At Rio's famed Maracana, Neymar scored after just 15 seconds for the fastest goal in Olympic history and added another in injury time as Brazil crushed Honduras to make the gold medal match.
The Barcelona star's brace bookended a 6-0 rout of Honduras, guaranteeing a place in the final against Germany as the hosts look to win a first ever Games football title.
"Neymar is a monster. He has the gift of playing football, he delights everyone with his talent," said Brazil coach Rogerio Micale.
Germany, who beat Nigeria 2-0, will face Brazil just two years after the European giants crushed them 7-1 in a traumatic World Cup semi-final humiliation.
Farah survived a trip from behind to secure his place in the 5,000m final.
The Briton, who recovered from a fall to retain his 10,000m crown last weekend, was clipped by American Hassan Mead but stayed on his feet to finish third in his heat and preserve his hopes of a double-double.
- Semenya eases -
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Semenya, the South African who has been at the centre of a gender controversy in recent years, breezed into the semi-finals of the 800m.
The 25-year-old is the overwhelming favourite to add a gold in Rio to the silver she won in London four years ago, with a 2016 time that is nearly a second faster than her closest rivals.
Kenya's Conseslus Kipruto stormed to victory in the men's 3000m steeplechase in an Olympic record of 8min 03.28sec for gold. American Evan Jager took silver.
Two-time Olympic champion Ezekiel Kemboi, also of Kenya, claimed bronze but was later disqualified for stepping on the infield.
Later on Wednesday, Bolt takes his latest step towards his 'triple triple' sprint gold in the 200m semi-finals.
With the first leg -- Sunday's electric 100m win -- secured, Bolt needs Thursday's 200m final and the 4x100 relay to achieve what he refers to as "immortality".
Darya Klishina, the sole Russian athlete allowed to compete at the Games, goes for gold in the women's long jump in the evening.
In badminton, Indonesia's Tontowi Ahmad and Liliyana Natsir defeated Chan Peng Soon and Goh Liu Ying of Malaysia to win the mixed doubles.
France won the team show jumping equestrian gold ahead of the United States and Germany.
World number two Ariya Jutanugarn of Thailand became the first player to top a women's Olympic golf leaderboard in 116 years.
The British Open champion fired a first-round 6-under-par 65 with South Korea's Park In-Bee and Kim Sei-Young both a shot back.
Away from the sporting action, Hickey, the head of the Olympic Council of Ireland, temporarily stood down from all Olympic roles after his arrest over illegal ticket sales.
Hickey, 71, was arrested at his Rio hotel after being accused of ticket scalping, ambush marketing and conspiracy.
