With clean technique down the rail section and a big 900 to close her Jeep Ski Slopestyle Women's run on Sunday at X Games Aspen 2013, Norway's Tiril Sjastad Christiansen -- an X Games rookie and, at 17, the discipline's youngest gold medalist -- pulled off an upset win against the most dominant skier in the history of women's Ski Slopestyle, Kaya Turski.

"I'm just so excited," Christiansen said afterward while in tears. "I crashed in my first run, but then I was able to land my run on the second and third runs. I couldn't be happier."

Looking for a historic fourth straight gold medal at Aspen, Canada's Turski, who also has three gold medals in Ski Slopestyle from X Games Tignes, crashed on her first two runs and was sitting in last place going into her final run of the event. To claim the history-making four-peat, the 24-year-old -- who posted the highest ever Slopestyle score (96.66) at this event three years ago -- needed to beat Christiansen's 92.33.

Adding to the pressure, the start of Turski's critical run was delayed for 35 minutes as medical staff tended to Ashley Battersby, who injured her left leg on a switch 900 attempt on the final jump of her third run.

Earlier, during the warmup session, Rose Battersby (no relation to Ashley) crashed on a jump. She suffered a lumbar spine fracture, according to X Games Medical, and was being transferred to Denver.

When Turski finally dropped in, her composure was clearly intact as she put down a solid run that included a rodeo 540, a switch 720, and a switch cork 540. It wasn't enough for gold, but Turski's score of 90 bumped her to second place.

"I'm just so relieved," Turski said. "I had a really rough time on my first two runs falling on a box that wasn't giving me any trouble all week. I'm stoked I brought the rodeo trick to my comp and I pulled it off after all the waiting at the top."

Turski said she kept her calm at the top of the course with help from her dad and her coach.

"I was just trying to lay low," Turski said. "At a certain point, I was just like, let's go with the flow."

Another X Games Aspen rookie, 18-year-old Canadian Dara Howell, who held the lead momentarily in the middle of the second round of runs, took home the bronze.

The contest produced another X Games first as Utah's Jamie Crane-Mauzy, who placed seventh, became the first female to land a double backflip in competition.