Monaco - New kid on the block Noah Lyles will test himself over 100m against veteran Justin Gatlin at Friday's Diamond League meet in Monaco, the young American seemingly set to take up the sprinting baton heading into the Doha world championships.

Lyles, 21, has never made the US team for an international competition, but has shone this year, becoming the fourth fastest sprinter ever over 200m when he blasted to a scintillating 19.50 in Lausanne last week.

It was the quickest time run over the half-lap race since Jamaican sprint king Usain Bolt won 200m gold at the 2012 Olympic Games in London.

Compared to his greenback compatriot, Gatlin is a long-standing fixture on the track, albeit a controversial one.

The 37-year-old won Olympic 100m gold back in Athens in 2004 in a race Lyles admitted he had watched years later.

"Yes, I saw it, I'm a student of the sport," said Lyles, who was just seven when Gatlin streaked to his first global gold.

Gatlin went on to win double gold in the 2005 world championships in Helsinki before being banned for doping between 2006-2010.

He returned to the track, most recently claiming 100m world gold in London ahead of his compatriot Christian Coleman and Bolt, openly crediting his longevity to the time he spent off the track.

Gatlin is also in form, the 9.87 he ran in the Prefontaine Classic making him the fourth fastest man this season.

In the post-Bolt era, he has been quick to praise the growing pressure, notably from US athletes, and also the increasing unpredictability of races, comparing them to a gunfight at the OK Corral.

Where before sprinters were realistically only fighting for the minor places, more often than not having been left in Bolt's wake, every race nowadays has a real sense of live competition.

"It's not always a clear favourite so you always have to be on top of your game and I like that a lot," said Gatlin, the meeting record holder in Monaco with 9.78 in 2015.

The Monaco meet, the eighth on the 14-leg Diamond League circuit, is traditionally one of the most attractive, with near-guaranteed hot weather and the fast track at the Stade Louis II often guarantees some cracking racing.

This year, there is also a loaded field in the women's 200m, with Shaunae Miller-Uibo of the Bahamas, the reigning Olympic 400m champion, pitched against Jamaica's Elaine Thompson, who won the sprint double in Rio.

Two-time defending world 200m champ Dafne Schippers of the Netherlands, American Jessica Prandini, Nigerian Blessing Okagbare and Marie-Josee Ta-Lou of the Ivory Coast also take part.

Kenyan Timothy Cheruiyot, with a season-leading time of 3:28.77, heads up a strong cast in the men's 1 500m, which also features two of the Ingebrigtsen brothers, European 1 500m and 5 000m champion Jakob - still just 18 - and world 1 500m bronze medallist Filip.

Elsewhere, Ethiopian Genzebe Dibaba goes in the women's mile, doubtless with a shot at another world record on the cards. She already holds records for the 1 500m (indoor and outdoor), 3 000m indoor, 5 000m indoor and the indoor mile.

But there will be no Caster Semenya. The South African is not appearing in the Principality despite having been cleared to run during her appeal at attempts by the Monaco-based world governing body for athletics, the IAAF, to introduce rules requiring female athletes in events between 400m and 1 500m to take medication to reduce high testosterone levels.