It was a case of double Dutch disaster on day one at the World Athletics Championships, with superstars Sifan Hassan and Femke Bol both crashing to the track in the shadow of the finish line with gold medals seemingly in their keeping.

Hassan came into the world titles seeking an improbable treble in the 1500 metre, 5000m and 10,000m.

Those dreams were dashed on Saturday in Budapest as she fell heavily 20m from home in the 10,000m final after tangling with Gudaf Tsegay, who took advantage of Hassan's misfortune to lead an Ethiopian medal sweep.

Hassan had won the 5000m and 10,000m titles at the Tokyo Olympics and was the 1500m bronze medallist.

"I think I got pushed by the Ethiopian," said Hassan, who had won her 1500m heat earlier in the day.

"I hope I am not crazy. I will need to look at the replay to see what exactly happened."

The replay appeared to show there was no push.

Bol suffered a remarkably similar fate less than half an hour later.

She looked certain to anchor the Netherlands to victory in the mixed 4x400m relay final, before cramping and falling over.

The incident happened so close to the finish that the Dutch baton — which fell from Bol's grasp — crossed the line before American Alexis Holmes.

"I don't know what happened, I cramped towards the finish line, I was pushing, pushing, pushing," Bol said.

"I was disappointed that my body did not have it in it to finish the race strongly.

"I'm sorry for my team, I should have finished it off."

Browning creates 28-year first with semifinal spot in 100m

Rohan Browning lived his mantra of doing the ordinary extremely well, becoming the first Australian man in 28 years to claim a berth in the 100m semifinals at a world athletics championships.

Browning was pipped for first place in his heat in a photo finish on day one in Budapest, with Botswana's Letsile Tebogo credited with the win after they both stopped the clock at 10.11 seconds.

It mattered little to the Australian, who had already turned his attention to the semi-finals on Sunday (early Monday AEST).

"It felt really smooth," the 25-year-old Sydneysider said.

"I've been searching for that last 20 metres of my race all year and I feel like I've finally found it.

"I felt like I missed the start a bit but I was able to take control and run through.

"I'm totally cognisant that it doesn't end with the heat."

The last Australian male sprinter to reach this stage in the 100m at a world championships was Damien Marsh in 1995.

"I've just felt a lot more composed this year, I've been in great health and I'm confident in my training, which is really worth its weight in gold," said Browning, who set his PB of 10.01 at the Tokyo Olympics.

"The things I have to do are all ordinary but if I do them all together then hopefully I can run at an extraordinary level."

Denny through to final after shaky start in discus

Australian powerhouse Matthew Denny was in no mood to sugar coat things after a nervy discus qualifying performance.

The Queenslander was staring down the barrel of a rare early exit before a moderate last-ditch effort of 64.29m saw him advance in ninth spot for the 12-man final on Monday evening (early Tuesday AEST).

Now he gets another shot at what would be a first major medal.