Nia Ali will have her three children who she says are her "toughest critics" in the stadium as she bids to regain her 100m hurdles world title in Budapest, beginning with the heats on Tuesday.

 The 34-year-old 2019 world champion's chances of doing so have become even more difficult with Nigerian world record holder and defending champion Tobi Amusan being cleared last week of a doping offence by the Athletics Integrity Unit, allowing her to run.

"I look forward to seeing her on the start line," said Ali of Amusan.

"All the better for us as it means faster times."

Amusan adds to a top-quality field which also includes former world record holder Kendra Harrison and Olympic champion Jasmine Camacho-Quinn.

Ali is in sublime form – she is the world leader this year with a time of 12.30sec at the Monaco Diamond League meet and was crowned US champion at the trials.

Ali, who missed the delayed Tokyo Olympics in 2021 after giving birth to her third child in May that year, says her professional life and her domestic one are easily compartmentalised.

However, she is prepared to get a flea in her ear if she fails to meet her kids' expectations.

"They keep me very humble," she said on Friday.

"They are straight shooters when they see me race and they get the video immediately after.

"If I do not win they ask 'what happened? You fell last time, perhaps you did not recover from this?'

"They are my toughest critics."

‘PUTTING PRESSURE ON ME’

Ali, though, says the trio – the father of the youngest two is Canada's Olympic 200m champion Andre de Grasse – are equally supportive of her.

"When I come home from training they say how proud they are," she said.

"They then give me space and go and play.

"They understand the competitive nature of the sport and they show the true strength of family values.

"They keep me strong. I am excited they will be here, they will be getting their hair done and then putting pressure on me."

Camacho-Quinn, though, will look to give herself a late birthday present as she turns 27 on Monday.

The Puerto Rican comes into the championships desperate to turn last year's bronze medal into a gold.

She could not be in better shape as she is unbeaten in 10 races this season.

Harrison's talent is unquestionable but at 30 a major outdoor global title still eludes her.

She has had to make do with two silvers – in the Olympics she finished behind her former training partner Camacho-Quinn and she had to give second best to Ali in the 2019 world championships in Doha.

Perhaps most galling was breaking the world record in 2016, weeks after missing out on Olympic selection. The American trio who did go to Rio swept the medals, including Ali who took silver.

However, Harrison is far from downbeat about her prospects, even if she fails to win in Budapest, of one day standing on top of the podium.

“My coach (Bobby Kersee) says that (you'll peak) in your early 30s," she said.

"So as long as my coach is on my side, I don't really care what others say."