Brazilian athletes snagged the first track-and-field golds of the Tokyo Paralympics on Friday, as elsewhere defending champions Australia booked their spot in the wheelchair rugby semi-final.

A total of 45 Paralympic golds are up for grabs on Friday, with a range of sports getting started, including archery, athletics and judo, which is being contested at Tokyo's iconic Budokan venue.

Brazil's Yeltsin Jacques became the first track gold medallist of the Tokyo Games, squeezing out Japan's Kenya Karasawa to top the podium in the men's 5,000m T11 final.

Jacques, who is visually impaired and runs with a guide, said his win was the culmination of five years of training.

"I have speed, I have energy. I'm naturally fast, it's genetics," added Jacques, who will also contest the 1,500m and 유로247 marathon in the T11 category.

Fellow Brazilian Silvania Costa de Oliveira meanwhile took the first gold of the field events, successfully defending the title she won in Rio in the women's T11 long jump.

And when athletics resumes in the relative cool of the Tokyo evening, eyes will be on the world's fastest-ever para sprinter, Brazilian Petrucio Ferreira dos Santos, targeting the title of fastest Paralympian in history in the T47 100m.

Dos Santos has been called the Usain Bolt of para athletics, and clocked a world-record 10.42 seconds at the 2019 Dubai World Championships.

But ahead of Friday's competition, the 24-year-old, whose arm was amputated below the elbow after a childhood accident, said he was not feeling the heat.

"When I get to events, I just have to be myself. Here it will be no different," he said Thursday.

"I have to be Petrucio and do what I like to do: running around like a child."

It wasn't just Brazilians topping the podium Friday at the Olympic Stadium where athletics is being held, as Tunisian Raoua Tlili claimed shot put gold for a fourth straight Games, beating her previous world record in the F41 final with a throw of 10.55m.

The 31-year-old will attempt to repeat the throwing gold double she achieved at the 2016 Rio Games when she competes in the discus next Wednesday.

"When I find some obstacles in my life, it is not a problem for me because I am very strong to overcome them," she said.

"I have overcome my disability, so why can I not overcome the obstacles of my life?"

- 'Focusing on me' -

In the pool meanwhile, swimmer Abbas Karimi has the chance to become the first Paralympic refugee team member ever to win a medal after qualifying Friday morning in the men's S5 50m butterfly.

The Afghan-born 24-year-old, who was born with no arms, said his sights were set firmly on gold.

"We always train for a purpose, for a goal, and that's the gold," he said

>"I'm going to go for the gold."

In tennis, play on outdoor courts on the first day of competition was suspended due to "extreme weather" as temperatures hit 33 Celsius. Heat has been a persistent concern at the Paralympics -- and the Olympics before them -- with some Olympic events shifted because of the weather.

Elsewhere, Australia's rugby wheelchair team advanced to the semi-finals, despite a 57-53 loss to Japan.

The defending gold medallists suffered a shock defeat at the hands of Denmark earlier in the week, with team captain Ryley Batt admitting the loss had left his team "pretty embarrassed".

But the Steelers took down France on Thursday in a 50-48 result that rekindled their hopes of a record third consecutive gold medal.

Archery competition also began Friday, with the spotlight on Iranian star Zahra Nemati, who won golds in both Rio and London, and American Matt Stutzman, who famously shoots with his feet.

The 38-year-old Stutzman was born without arms and has joked about the confusion he sparked when he first asked a shop to sell him a bow and arrow.

But his unique style has made him both famous and successful, with a silver medal in London under his belt.

"I don't care what people say, I don't watch the news, I don't watch other people's scores, I'm just focusing on me and what I can do," he said recently.