The American women's sprint relay quartet pulled off a stunning upset over Jamaica at the World Championships on Saturday while a flubbed baton handover proved costly for the U.S. men's team as they finished second to Canada.
Jamaica were anchored by new 200 metres champion Shericka Jackson but Twanisha Terry ran a terrific final leg to bring home the hosts' 10th gold medal in Eugene.
"It's just an amazing feeling," Terry said. "The race was electrifying. The stadium went crazy."
Germany took a surprise third-placed finish after Britain's Dina Asher-Smith pulled up injured.
The United States had looked set to retain the men's title until Elijah Hall and Marvin Bracy lost time with a slow exchange, the latest disappointment for a country with incredible depth of sprinting talent.
Andre De Grasse, the Olympic 200m champion, beat Bracy to the finish line while Britain collected bronze.
"It's special to win here. There are many Canadians cheering us on. It's not on home soil, but it felt like it," De Grasse said.
Portugal's Pedro Pichardo (triple jump) and Kenyan Emmanuel Korir (800m) added world titles to their Olympic crowns but Canada's Damian Warner, also a gold medallist in Tokyo, suffered injury heartbreak in the decathlon.
Pichardo jumped a world-leading 17.95m to take gold ahead of Burkina Faso's Hugues Fabrice Zango and China's Olympic silver medallist Zhu Yaming.
Korir produced his trademark devastating kick to clinch the 800m title with Algerian Djamel Sedjati taking a surprise silver ahead of Canada's Marco Arop. (Reuters)