KRASNAYA POLYANA, Russia >> Alla Tsuper of Belarus pulled off a stunning upset to win gold in women’s aerials on Friday, beating a field that included two decorated Olympians.

Tsuper drilled a 98.01 in the finals to knock off defending champion Lydia Lassila of Australia and two-time medalist Li Nina of China.

Xu Mengtao of China won silver, while Lassila earned bronze.

The 34-year-old Tsuper had never finished higher than fifth in four previous Olympics. She plans on retiring after the games to spend more time with her young daughter and hoped to go out "on a high."

Tsuper went first during the four-skier final round and nailed her acrobatic leap. Nina and Lassila both botched their landings and when Mengtao struggled to hold on at the end of her jump, Tsuper began celebrating.

The victory came out of nowhere. Tsuper competed only sporadically after finishing eighth in Vancouver. She took time off to start a family and had finished on the podium just once at any level since returning to competition six months ago.

It hardly mattered in spring-like conditions as Tsuper warmed up after some early jitters. She washed out in her first qualifying jump and her second wasn’t much better. Her score of 77.52 made her last among the 12 who advanced to the first round of finals.

She only got better as the field thinned from 12 to eight to four. Tsuper put up the top score in the first round and nudged her way into the final with a score of 88.50 in the second round.

The decision was easy in the last round of elimination. She nailed her back triple full — basically three back flips with three full twists — and pumped her fists upon landing.

Nina, in search of gold after two runner-up finishes, landed face first in the snow after coming up short on her landing. Lassila sat down after her final jump and Mengtao — a two-time World Cup champion who has struggled this winter — momentarily lost her balance after her skis smacked the snow.

The gold was the third for Belarus in Sochi and the first by a Belarussian woman in freestyle skiing.

American Ashley Caldwell led qualifying, posting the highest score with a backward flipping triple twist jump, which had the highest degree of difficulty in the round. But the 20-year-old from Ashburn, Va., who tore the ACL in her right knee in 2011 and the ACL in her left knee in 2012, stumbled in the finals. She sat down at the end of her back layout triple twisting leap, dropping her to 10th place and out of the next round.

Veteran Emily Cook made it to the second round of finals, but could not advance. The 34-year-old, born in Belmont, Mass., and currently living in Park City, Utah, said afterward this will be her final Olympic appearance.