A new Olympic sport makes a sweltering start.

After decades of trying to get into the Olympics, skateboarding makes its debut with the men’s street contest at sweltering, sun-baked Ariake Urban Sports Park. Twenty men qualified for the event, and by midday Sunday in Tokyo, the first skateboarding gold medal will be awarded.

We arrived 90 minutes before the first heat, and skaters were already warming up, quite literally. Temperatures were expected to be in the 90s, and shade is almost nonexistent. As with most skate contests, there is music and an upbeat announcer. There is no crowd, of course, other than a swarm of sweating reporters sitting on one end.

The most attention will fall to Nyjah Huston, the 26-year-old American widely regarded as the best contest street skater in history and the subject of a deep New York Times profile this week. He has won all the major events of skateboarding, including world championships, the Street League Skateboarding series, the X Games and the Dew Tour events. His home in Laguna Beach, Calif., has a trophy room that can barely contain all the trophies and medals. He is likely to squeeze in one more here at the Olympics.

His biggest challenger for gold is a local skater, the 22-year-old Yuto Horigome, the son of a Tokyo taxi driver (we wrote about that, too) and Huston’s biggest rival the past couple of years. In the first major post-pandemic events this spring, Huston won a Dew Tour contest, and Horigome then won the world championship in Rome. If there is an upset here, it will be that the two of them do not finish 1-2, in either order.

But the field is deep, and plenty of athletes arrived with realistic medal hopes. The Americans Jagger Eaton and Jake Ilardi are among them. With skateboarding’s four events at the Olympics (men’s and women’s street and men’s and women’s park), the safe bet is on one of three countries: the United States, Japan and Brazil. But there are outliers, and it would not be a surprise if, say, Vincent Milou of France skated to a medal today.

Here’s the format: The athletes were divided into four heats of five skaters. Each will perform two timed runs through the skate park, hustling through their own path over the rails, bumps and ledges. Falling does not disqualify anyone, but it will not help their scores.

The skateboarders will also get to attempt five tricks of their choosing. A panel of judges will score each run and trick — seven in all — on a 10-point scale. The best four scores are added together.

The skaters with the top eight scores will advance to the final. All of the preliminary scores are scrubbed, and the process repeats from scratch. Before these athletes go to lunch, someone will have won a gold medal.

The skateboarders have spent the past few days practicing at the park, an hour or two a day, trying to figure out which features to hit and string together. The response to the park is universal — it is big, fun and incredibly hot.