Britain's Emelia Gorecka won the Great Edinburgh Cross Country women's race, as GB finished last in the team event.
Gorecka, 20, finished the 6km race in Holyrood Park in 21 minutes 26 seconds, with Ireland's Fionnuala Britton second and Ethiopia's Trihas Gebre third.
American Chris Derrick won the men's 8km race, holding off team-mate Jacob Riley to defend his title.
USA won the team event on 121 points, with Europe second on 189 and Britain in third and last place on 223.
The defending team champions were without Olympic 5,000m and 10,000m champion Mo Farah who pulled out this week because of illness.
Gorecka finished a disappointing 12th in the European Cross Country Championships in Bulgaria last month.
But she bounced back with an impressive performance in blizzard conditions.
"I'm completely overwhelmed," she told BBC Sport. "I came away from the Europeans heartbroken but I refocused, battled on and put in a good performance today.
"It's my first major senior win. It feels amazing. I tried to run smart and clever and fight with all my heart."
USA team captain Derrick won in a time of 25 minutes 31 seconds with Britain's Jonathan Hay and Charlie Hulson third and fifth respectively.
"It was a great team performance," said Derrick. "There was no real weak link and it was a hard-fought win."