Karsten Warholm smashed his own world record as he streaked to victory in the Olympic 400m hurdles on Tuesday while Simone Biles prepared for a dramatic return to action after a Games dogged by mental health struggles.
Norway's Warholm lit up the Olympic Stadium in the final event of the morning session, clocking a remarkable 45.94 seconds to destroy his previous world best by nearly 0.8sec.
The 25-year-old dominated the race, with long-time rival Rai Benjamin taking silver and Brazil's Alison dos Santos claiming bronze.
Warholm roared in apparent disbelief as he spotted his winning time, dropping to his knees.
"Man it's so crazy, said the Norwegian, already a two-time world champion. "It's by far the biggest moment of my life. It defines everything, all the hours I put in, everything that my coach has been working for.
"I dream about it like a maniac, I tell you. I sleep all night on it. I spend all my time thinking about this, so just getting this last medal into my collection, it’s complete."
Germany's Malaika Mihambo soared to gold in the women's long jump, snatching victory from former champion Brittney Reese with her last leap of the competition.
Mihambo, 27, was lying in the bronze medal position ahead of her final jump, but powered down the runway to register a season's best of 7.00 metres and Reese could not respond. Nigeria's Ese Brume took bronze.
"It was, I think, the most exciting women's long jump competition in history," said Mihambo.
"It was so exciting to be part of and I am happy I made it at the end."
Veteran US sprint queen Allyson Felix made it safely through to the women's 400m semi-finals as she launched her quest for a record-breaking 10th Olympic medal.
The 35-year-old needs one more medal in Tokyo to become the most decorated female track and field athlete in Olympic history, a title she shares with Jamaica's Merlene Ottey, with nine medals.
Another world record holder, Sweden's Armand Duplantis, is a hot favourite in the men's pole vault final, which takes place in the evening session in Tokyo without US world champion Sam Kendricks, who withdrew after a positive coronavirus test.
Tuesday's athletics schedule concludes with what promises to be a thrilling women's 200m final, with Jamaica's Elaine Thompson-Herah seeking an unprecedented women's sprint "double-double".
The 29-year-old, who won the 100m and 200m at the 2016 Rio Games, looks most under threat in the final from her compatriot Shelly-Ann Fraser-Pryce, whom she beat to gold in the 100m.
Thompson-Herah, who recorded a blistering 21.66sec in the semi-finals, also faces a threat from 2016 400m winner Shaunae Miller-Uibo, rising US star Gabby Thomas and Namibian teenager Christine Mboma.
American superstar gymnast Biles, who won four gold medals in 2016, came to Tokyo with her eyes on equalling the all-time Olympic record for a female competitor of nine.
But the 24-year-old has been struggling with the "twisties", a condition that affects gymnasts' ability to orientate themselves in mid-air.
She dramatically pulled out of last week's team competition final after one vault as Team USA took silver, and said she feared for her mental health.
The 19-time world champion subsequently withdrew from the all-around final and three of the four apparatus finals -- the floor, vault and uneven bars.
But Biles will be back in the last women's final of the Games, on the beam, and under intense scrutiny.
Although it is not her strongest apparatus, Biles is a three-time beam world champion in the discipline and took Olympic bronze in 2016. Victory would be one of the great comeback stories.
Elsewhere on day 11 of sporting action in Japan, British track cyclist Jason Kenny attempts to win his seventh Olympic gold while his wife Laura Kenny, who has four gold medals, is in action in the women's team pursuit.
Belgium beat India 5-2 in the semi-finals of the men's hockey competition, ending India's hopes of a first Olympic gold medal in the sport since 1980.
Away from the sporting action, Belarusian athlete Krystsina Tsimanouskaya was sheltering in Poland's embassy in Tokyo after being offered a humanitarian visa.
Tsimanouskaya claims her team attempted to force her onto a plane after she criticised her coaches and says she fears for her safety if she returns to Belarus.
By: John Weaver/ AFP