Fred Kerley will bid to retain his world 100m crown in Budapest on Sunday, but the blue riband event of track and field is arguably as open as it has been in 20 years.

For once, there is no clear favourite for the shortest speed event although Kerley and US teammate Noah Lyles were quick Friday to dismiss any fears of the threat posed by Olympic champion Marcell Jacobs.

Jacobs has only raced outdoors once this season, finishing seventh in 10.21 seconds at the Paris Diamond League race won by Lyles last month.

"I know what form he's in, we all saw it," Lyles said with a grin when asked what Jacobs might bring to the track.

Another question on the Italian sprinter saw Lyles retort to Kerley: "Damn, Fred, this man is popular, how did this man get so popular?"

Kerley replied: "I don't know, man, we're not too worried about him at this moment."

Kerley has raced just five 100m races this season, two of them in Yokohama in May, where he clocked a season's best of 9.88sec.

He registered comfortable victories on the Diamond League circuit in Rabat and Florence, both in 9.94, but was edged out by South Africa's Akani Simbine in a tight finish in Silesia last month.

Lyles will be gunning for a third world 200m title and a potential sprint double, with the US quartet in the 100m also comprising Cravont Charleston and the 2019 world champion Christian Coleman.

HUGHES IN WINGS

The world leading time this season was set by Anguilla-born Briton Zharnel Hughes, whose 9.83sec in New York in June bettered former world champion Linford Christie's British record by four-hundredths.

Hughes is coached by legendary Jamaican coach Glen Mills, the sprint guru who guided Usain Bolt to victory in 2009, 2013 and 2015, and also Yohan Blake in 2011.

"Obviously people are going to target the time I've run,” said Hughes, who false started in the final at the Tokyo Olympics.

"But I don't put pressure on myself. That's when things can go topsy turvy."

The last sprinter from outside Jamaica or the United States to win the world 100m crown was Kim Collins of St Kitts and Nevis, way back in Paris in 2003.

And one look at potential podium contenders suggests that the scene could well be set for that duopoly to be broken.

A trio of Africans, on their day, are more than capable of taking the world by storm, albeit having to negotiate an opening round on Saturday before a semifinal and final 24 hours later.

Second in the season's fastest times sits Kenyan Ferdinand Omanyala (9.84), with the Commonwealth champion the only sprinter to have dipped under 9.90 twice this year.

Botswana's Letsile Tebogo and South African Simbine have both shown form that raises hopes of there being a first African medal winner in the event.

Unlike their female counterparts, the Jamaican men's sprinters have struggled in recent years and their challenge in Budapest will be led by Oblique Seville, who finished fourth in the Eugene worlds, and national champion Rohan Watson.

As for Jacobs, the surprise Olympic champ insisted he wanted to have the favourite tag going into the race after a "rollercoaster" of a season.

"It hasn't been an easy season for me, there have been a lot of doubts, a lot of worries, but I'm here," admitted the 28-year-old Italian, who was forced to pull out of Eugene.

"I have faced many challenges over the last two years, but I've been working hard for these world championships.

"It's a very open challenge and I'm looking forward to it. I am used to always feeling there are eyes on me and watching me."