Twenty months after he rose from anonymity to claim Olympic gold in track and field’s glamour race, Marcell Jacobs could no longer outrun the talk that he was afraid to risk exposing himself as a one-hit wonder.

The whispers began last summer when Jacobs pulled out of a string of marquee meets, citing illness or injury. Then the man who finished second to Jacobs in the 100m in Tokyo amplified the criticism when he implied that the Italian was purposefully dodging elite competition.

“Real dogs come and play outdoors,” Fred Kerley, the reigning 100 meters world champion, told a track and field podcast earlier this spring. When the host asked the American if Jacobs was a “real dog,” Kerley matter-of-factly responded, “I don’t think so. I’m just being truthful.”

In response, Jacobs hopped on Instagram in April and posted a photo of himself out-leaning Kerley at the finish line at the Olympics. Jacobs captioned the photo: “Whenever you want and wherever you want, but remember that when it mattered more it ended like this.”

At last, two of the world’s fastest men will finally have the chance to back up their bold talk. The reigning Olympic and world champions are scheduled to clash twice in six days in their first head-to-head races since Jacobs edged Kerley at the 2021 Tokyo Games. They’ll first highlight a star-studded men’s 100 meters field on Sunday evening at a Diamond League meet in Rabat, Morocco. Up next for both men is another Diamond League showdown the following Friday in Florence, Italy.

At stake for Jacobs and Kerley is something less than Olympic or World Championship gold but something more than just bragging rights. Both men are seeking to establish themselves as the best male sprinter of track and field’s post-Usain Bolt era.

It is widely accepted across track and field that there will never be another Bolt. There will never be another track and field athlete with his sublime combination of speed and showmanship, with his knack for rising to a big moment, with his ability to run faster and more joyously than should be possible and drag an entire niche sport in his slipstream.

And yet track and field did not shut down when Bolt unlaced his track spikes for the final time at the 2017 World Championships. The sport is still searching for a worthy successor, for someone to crown as its new sprint king.

It could be Jacobs if he can recapture his Olympic form and prove the summer of 2021 wasn’t a fluke. Or it could be Kerley if he can build on a dominant 2022 season that culminated with his first global gold medal at last July’s World Championships. Two upcoming head-to-head battles will provide an early barometer of how prepared both men are — and their recent war of words will only add to the intrigue.

“To me, the trash talk is great,” NBC track and field analyst and four-time Olympic medalist Ato Boldon told Yahoo Sports. “I know how much sprinters in my era didn’t like each other and now these two guys seem to have a legitimate beef. This is Linford Christie versus Carl Lewis, the guy who’s the best in Europe and who doesn’t really care for the brash American. Head-to-head matchups like this can only build interest.”

These types of matchups are rare in track and field, Boldon said, because “meet organizers can’t afford them.” When asked how large an appearance fee the likes of Kerley and Jacobs could command, Boldon said he “couldn’t see either of them running for less than $50,000.”

As recently as three years ago, a 100 meters race featuring Jacobs and Kerley wouldn’t have been nearly so costly. Neither even specialize in the short sprints as young pros.

Jacobs broke into track and field as a long jumper, became the 2016 Italian champion in that event and to this day still uses “crazylongjumper” as his Twitter and Instagram name. Only after injuries slowed his ascent in the long jump did the former Italian champion decide in 2019 to shift his focus to the track.

At the same time that Jacobs was trying to find his niche in the sport, Kerley made an audacious decision to take a break from his signature race. Kerley, already the collegiate record holder in the 400 and 2019 World Championships bronze medalist, abruptly shifted to the 100 and 200 before the 2021 U.S. Olympic Trials. He had become intrigued by the potential he’d flashed in the shorter sprints that spring while dealing with an ankle injury that prevented him from correctly running the curve.

Jacobs’ and Kerley’s paths intersected in Tokyo when they both took advantage of the void left by Bolt and outperformed expectations on the world’s biggest stage. The Italian lowered his personal best in all three rounds en route to his longshot Olympic gold medal. The American won his semifinal heat and then finished four hundredths of a second behind Jacobs in the final.

That moment of glory ensured Jacobs will never buy his own glass of Sangiovese in his home country, but so far the Italian hasn’t duplicated that level of performance. Jacobs did not race again in 2021, citing exhaustion. Intestinal problems forced him to withdraw from a meet in Narobi in early May 2022. Then came a lingering thigh injury that disrupted the rest of his outdoor campaign and led him to pull out of the World Championships before his semifinal race.

Nearly a year later, Kerley and Jacobs are scheduled to meet again at last. The star-studded men’s 100 field in Rabat also includes ballyhooed African record holder Ferdinand Omanyala of Kenya, 2012 Olympic silver medalist Yohan Blake of Jamaica and 2022 World Championships bronze medalist Trayvon Bromell of the U.S.

Kerley, says Boldon, enters the race as the favorite over Jacobs, Omanyala and the rest. While Jacobs has yet to make his outdoor debut this season, Kerley already looks sharp. He surged down the stretch to clock a sub-20-second 200 at a Diamond League meet in Doha earlier this month. Then he ran 9.88- and 9.91-second 100s last weekend to win a meet in Yokohama, Japan.

“I have to see somebody beat Fred first before I’ll pick against him,” Boldon said. “Stranger things have happened, but he was favored all year last year and came through.”

Kerley, if anything, is even more confident. In response to Jacobs’ “Whenever you want, wherever you want …” Instagram story, Kerley wrote, “Keep that same energy because ducking is not what I do.” Kerley then tweeted the Diamond League account to “make it happen” and added that he wanted “1v1 no one else just him. Him alone.”

For now, Kerley will have to settle for a shot at redemption in a traditional 100 meters race with other formidable competitors alongside him and Jacobs. Asked earlier this month about facing Jacobs, Kerley said he “will definitely win.”

Then he shrugged his shoulders and added, “If he shows up, I don’t know.”