Team USA were reeling from an "embarrassing" relay display and a shock defeat for hurdler Grant Holloway on a rollercoaster day in Tokyo - where they also celebrated shot put gold and a guaranteed basketball medal.

That defeat was followed by world champion and overwhelming favourite Holloway being beaten by Jamaican Hansle Parchment in the men's 110m hurdles final, while there was no medal for the USA in the men's 400m, an event they used to dominate but which was won by Bahamas' Steven Gardiner.

There is a very real chance that the USA may fail to win a gold medal in a men's individual running event for the first time, not including the 1980 Games that they boycotted.

American spirits were lifted by Ryan Crouser beating his own Olympic record to defend his shot put title, a pole vault title for Katie Nageotte, and news that BMX rider Connor Fields was set to be released from hospital less than a week after a crash that left him with a brain haemorrhage.

The United States are second behind China in the medal table and will add to their tally after the men's basketball team reached Friday's final, while Nelly Korda is in a strong position in the women's golf, where she has a four-stroke lead after two rounds.

Away from the traditional powerhouses, Burkina Faso were celebrating a first-ever Olympic medal when Fabrice Zango took bronze in the triple jump and India ended a 41-year wait for a hockey medal.

And the first-ever gold medal was awarded in karate, where Spain's Sandra Sanchez Jaime triumphed in the women's kata, and in sport climbing, where her compatriot Alberto Gines Lopez claimed victory.

Meanwhile, Belgium's Nafi Thiam retained her heptathlon title and Canadian Damian Warner won the decathlon with an Olympic record score.

Are the United States underperforming on the track?

The verdict by Carl Lewis was damning as the American men's 4x100m team - made up of Trayvon Bromell, Fred Kerley, Ronnie Baker and Cravon Gillespie - finished sixth in their heat and failed to reach the final.

"The passing system is wrong, athletes running the wrong legs, and it was clear that there was no leadership," he said.

"It was a total embarrassment."

The USA are top of the athletics medal table with five golds and 20 podiums but with three days to go are a considerable way off the 13 golds they won at Rio 2016.

Four of their five golds have come from women, with the sole men's one coming in shot put as they continue to underperform in the individual track events.

In the 110m hurdles, Holloway was the hot favourite as he was unbeaten since August last year and had missed the world record by one-hundredth of a second at the US Olympic trials.

Holloway said nerves had got the better of him as he lost momentum over the final two hurdles and allowed Parchment to surge past him.

They also failed to win a medal in the men's 400m final, an event where they were once so dominant that they won seven titles in a row from 1984 to 2008.

And their defending 1500m champion Matthew Centrowitz finished outside the qualifying spots for Saturday's final.

But there was American joy in the pole vault, where Katie Nageotte won gold, and the shot put, where Ryan Crouser beat his own Olympic record to defend his title.

Crouser managed 23.30m on his final attempt, having led from the opening throw, in sweltering conditions at the Olympic Stadium.

Compatriot and world champion Joe Kovacs took silver with New Zealand's Tomas Walsh claiming the bronze.

It was the first time in an individual sport that the Olympic podium has not changed since the previous Games.

Colombia win first athletics medal & Thiam shines in heptathlon

The below-par showing by United States has been in contrast with the fortunes of other countries, who have managed their best ever results.

Colombia won their first athletics medal with Anthony Zambrano taking silver behind Steven Gardiner, who himself picked up the first individual Olympic title for a male track and field athlete from the Bahamas.

For Burkina Faso, it was a first Olympic medal full stop when they became the 100th nation to win an Olympic athletics medal as Fabrice Zango took triple jump bronze behind Portuguese winner Pedro Pichardo.

"Burkina Faso is really happy. Everybody is happy. I think they will throw a great party when I go back," Zango said.

The USA's neighbours, Canada, are enjoying contrasting fortunes with Damian Warner taking gold in the decathlon the day after Andre de Grasse triumphed in the 200m to give them two golds in 24 hours.

And for Belgium's Nafi Thiam, it was two golds in successive Games as she retained her heptathlon title.

Team USA into basketball & baseball final as footballers take bronze

Team USA are one win away from a fourth successive gold in the men's basketball after they beat Australia 97-78 in the semi-finals.

The Americans got off to a poor start though, letting Australia build a 15-point lead in the second quarter, before recovering.

The most successful team, with 15 basketball golds since 1936, have not been as dominant as in the past at these Games, suffering a first Olympic defeat since 2004 in their opening game against France.

They will face France again in Friday's gold-medal match after the French beat Slovenia 90-89 in a nail-biter.

And they also reached the baseball final by defeating South Korea 7-2. In what will be the first Olympic baseball final for 13 years, they will take on hosts Japan on Saturday.

Meanwhile, in football, the USA women - who were favourites for gold before a surprise semi-final defeat - clinched the bronze medal with a thrilling 4-3 win over Australia.

India end wait for hockey medal

India ended a 41-year wait for an Olympic hockey medal with a 5-4 win over Germany that earned them the bronze.

They are the most successful hockey nation in Olympic history with eight men's titles, but India's last medal until now was at the 1980 Moscow Games, when they won gold.

Belgium won their first Olympic men's hockey title, beating Australia 3-2 in a penalty shootout after the final finished in a 1-1 draw.

Cycling gold for Baspennincx & New Zealand record for Carrington

Dutch rider Shanne Braspennincx won Olympic gold in the keirin - six years after suffering a heart attack and not knowing if she would compete again.

Braspennincx, 30, crossed the line ahead of New Zealand's Ellesse Andrews and Canada's Lauriane Genest.

There was also a first Tokyo track cycling gold medal for Team GB, with Matt Walls winning the omnium on his Olympic debut.

But two-time defending champion Jason Kenny was beaten in the sprint quarter-finals, two days after he won his eighth cycling medal to become Great Britain's most decorated Olympian.

New Zealand, meanwhile, have a new most successful Olympian after Lisa Carrington won gold in the women's kayak single 500m, taking her overall Games medals tally to six.

Skateboarding win for Australia as Spain win Olympics' first karate gold

There were more medals in the sports that are making the debut at these Olympics.

Australian 18-year-old Keegan Palmer packed in the tricks to win gold in the men's park skateboarding event, with Brazil's Pedro Barros taking the silver and American Cory Juneau hanging on for bronze.

And among all the teenagers, who have lit up the new event, there were two 46-year-olds competing - Rune Glifberg and Dallas Oberholzer.

Meanwhile, in karate - which was introduced for these Games but unlike skateboarding will not be returning at Paris 2024 - the maiden gold medal went to veteran Sandra Sanchez of Spain, with local favourite Kiyou Shimizu taking the silver.

The gold first medal in sport climbing went to Spain's Alberto Gines Lopez, with silver going to American Nathaniel Coleman and bronze to Austrian Jakob Schubert.

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