Roberts, the 21-year-old American who won world titles in 2017, 2019 and 2021 but had to settle for a silver medal when the discipline made its Olympic debut a year ago, topped qualifying and turned that form into a gold medal at the Corniche venue.

Going last on run two with the pressure on, Roberts began with a bar-spin backfilp and scored 87.20 points for victory.

France's Nikita Ducarroz was second - as was the case at last year's World Championships in Montpellier - scoring 84.70 - and Czech Iveta Miculyčová completed the top three with 83.20.

Charlotte Worthington, the Olympic champion from Britain, came fifth.

Japan's Nakamura won by smaller margin than Roberts but could still boast daylight, posting a final score of 93.80 on his opening run and it proved to be enough for victory.

A bar spin, tuck no-hander with 720 degrees of rotation began Nakamura's triumphant run.

American Justin Dowell was second on 91.50 and France's Anthony Jeanjean third on 91.20.

Next year's competition will be in Glasgow, which is hosting the International Cycling Union's inaugural Cycling World Championships - an event aimed at uniting all of its disciplines.