The underdog even if he had the fastest time and No. 1 ranking coming in, Dos Santos held off a decorated field that included the world-record holder. Dos Santos finished in a championship-record time of 46.29 seconds. Americans Rai Benjamin and Trevor Bassitt won the silver and bronze.

Olympic champion and world-record holder Karsten Warholm of Norway has been dealing with hamstring issues and didn’t have his trademark kick at the finish. He wound up seventh.

Upon his finish, Dos Santos gave two bows to the cheering crowd. He broke Kevin Young’s world-championship record of 47.18 seconds set in 1993 in Germany. Dos Santos won bronze at the Tokyo Games last summer behind Warholm and Benjamin.

It was a night full of surprises with Jake Wightman of Britain winning the 1,500 meters. He had a look of disbelief as he crossed the finish line ahead of Olympic champion and heavy favorite Jakob Ingebrigtsen of Norway.

“Crazy,” Wightman said. Wightman finished in a time of 3 minutes, 29.23 seconds. His win broke a string of five straight world 1,500 titles by the Kenyans. Spain’s Mohamed Katir flew down the homestretch to take home bronze.

Other winners included Australia’s Eleanor Patterson in the women’s high jump and Kristjan ?eh of Slovenia in the men’s discus.

Earlier in the night, world 100-meter champion Fred Kerley slowed down midway through his 200-meter semifinal due to a cramp and finished sixth. His thoughts of two individual medals at the first worlds held on U.S. soil were dashed.

Kerley, once a 400-meter specialist who moved down in distance before last year’s Olympics, won the 100 in 9.86 seconds and was expected to lead the Americans in the 4x100 relay this weekend. He hasn’t been ruled out.

Kerley’s departure opens a less-challenging path for Noah Lyles, the defending world champion, 18-year-old Erriyon Knighton, and top-ranked Kenny Bednarek, all of whom advanced. The trio had the top three times, led by Lyles at 19.62 seconds.

The Jamaican women are poised for another sprint sweep after qualifying three for the final in the 200. Shelly-Ann Fraser-Pryce, Shericka Jackson and Elaine Thompson-Herah — the finishing order of the 100 — all advanced. Jackson had the fastest time at 21.67.

It was an easy night at the track for the medal favorites in the women’s 400 hurdles. Olympic champion and world-record holder Sydney McLaughlin, defending world champion Dalilah Muhammad and Olympic bronze medalist Femke Bol of the Netherlands easily won their first-round heats.

“This event has become one of the main focuses for the last couple of years,” Muhammad said. “It could be any one of our days. So we’ll just see how it goes.”