Riley Day smashes her 200m PB in Tokyo

Australian sprinter Riley Day has smashed her 200m personal best in the semis of the Tokyo Olympics.
Australian sprinter Riley Day has smashed her 200m personal best in the semis of the Tokyo Olympics.

Jamaican Elaine Thompson-Herah is just one win away from an unprecedented Olympic women's sprint double-double after dominating the 200m semi-finals in Tokyo.

Rising Australian star Riley Day, 21, gave a tantalising glimpse of what she could achieve in the next few years by smashing her PB with a time of 22.56 seconds to just miss out on a spot in Tuesday's final.

But the woman to beat right now is Thompson-Herah, whose winning semi-final time of 21.66 was way clear of the second-fastest qualifier, Namibian teenager Christine Mboma (21.97).

The 31-year-old Thompson-Herah led a Jamaican clean sweep in the 100m final in Tokyo on Saturday, having previously topped the podium in both the 100m and 200m five years ago in Rio.

Her great domestic rival, two-time Olympic 100m champ Shelly-Ann Fraser-Pryce, also booked a spot in the 200m gold medal race after winning her semi in 22.13.

Day will be watching on from the sidelines on Tuesday night.

But she still took a huge step forward on her Olympic debut, leaving the likes of Rio Games 200m silver medallist Dafne Schippers and American Jenna Prandini in her wake in the semis.

"That is a massive PB, that's awesome," Day told the Seven Network.

"I don't like to let (my inexperience) stop me.

"I want to be the best and I'm going to stop at nothing to be the best."

Earlier on Tuesday, Day overcame an understandable pre-event bout of nerves to ease her way out of the opening round in 22.94, after which she promised to "absolutely floor it" in the semis.

She was as good as her word.

Mdoma will be joined in Tuesday's night's final by her countrywoman Beatrice Masilingi.

Both of the Namibians are better known as 400m runners.

They are among the group of women banned by World Athletics from competing in races between 400 metres and one mile unless they agree to take medication to reduce their high natural testosterone levels.

It is the same rule that prevented South African Caster Semenya from chasing a third successive Olympic 800m title in Tokyo.

London Olympics finalist Steve Solomon finished strongly to finish third in his men's 400m semi in 45.15, but it wasn't enough to book a berth in the final on Thursday.

The Sydneysider had bettered his PB for the first time in nine long years in the heats on Sunday.

"I really gave it everything I had today," said Solomon.

"I came into the race feeling really confident but was just a little short in the legs tonight."

Grenada's Kirani James, the 2012 Olympic gold medallist, was quickest in the semis in 43.88.

Just behind James were Colombian Anthony Jose Zambrano (43.93) and Steven Gardiner from the Bahamas, who clocked a slick 44.14 even though he ran in a baggy T-shirt rather than the usual skin-tight racing attire.

Australian Associated Press