Williams established a lead with 88.66 points in his first run, extending it with 91.33 on run two.

United States competitor James Foster, 26, moved up to challenge him with a third-round score of 87.66, but Williams looked secure enough until his fellow Australian Vince Byron took over as leader with his final effort, scoring 91.66.

Williams rose to the challenge, but there was a tense wait before the judges announced that he had done more than enough to deny Byron what would have been his first X Games big air gold with a score of 93.00.

Earlier in the day, X Games legend Leticia Bufoni added a fifth gold to her collection as she won a highly competitive women’s skateboard street final.

The  26-year-old Brazilian, named at 25 by Forbes as one of the most powerful women in international sport for 2018, put it out there with the first of her three runs as she scored 84.33 points.

That was never headed, although Australia’s 17-year-old Hayley Wilson almost earned a dramatic victory with her third attempt, taking silver with 83.00.

US architect Alexis Sablone, 32, took bronze with 81.66.

Jackson Strong was winner of the motocross best trick with 97.33, ahead of Adelberg, who scored 96.66, and Tom Pages, who had a best of 95.00.

Tokyo’s 20-year-old Yuko Horigome topped the opening men’s skateboard street with a best of 85.66 points ahead of Dashawn Jordan, who scored 84.00, and Vincent Milou, who had a best of 83.66.

This annual extreme sports event hosted, produced and broadcast by ESPN had its inaugural showing in 1995 and has been arranged annually since 1998.

Action concludes tomorrow with the BMX street final, the motocross best whip, the men’s skateboard street and skateboard big air final.