* Canadian domination continues for third Games
* Serwa wins gold, Phelan silver
* Switzerland's Smith takes controversial bronze
* Defending champion Thompson crashes out in heat (Adds detail, quotes)
PYEONGCHANG, South Korea, Feb 23 (Reuters) - Kelsey Serwa pulled away from compatriot Brittany Phelan to claim ski cross gold on Friday as Canada secured a one-two finish ahead of Switzerland's Fanny Smith, who edged out Swede Sandra Naesland in a bustling battle for bronze.
Serwa's comfortable victory enabled Canada to continue their domination of the event, the country having now won all three ladies ski cross golds since it was added to the Olympic programme at Vancouver in 2010.
The 28-year-old Serwa improved on her silver medal from Sochi four years ago but it was a bittersweet event for the Canadians after reigning champion Marielle Thompson crashed out in the first heat, catching the ski of Sweden's Lisa Andersson.
There was also a worrying crash for the fourth Canadian, India Sherret, who lost control entering a jump in her heat, before flying over the top and into a hard bank of snow.
The extent of her injuries remains unclear, although the Canadian team confirmed Sherret was in a stable condition and being assessed at a hospital.
With two Canadians in the final, it promised to be yet another fruitful return for the team and so it proved as Smith and Naesland become embroiled in an early barging match, leaving their two rivals a chance to pull away.
"It was just great. It was just perfect," an ecstatic Serwa told reporters after crossing the line ahead of her best friend. "There are no secrets between us because we want each other to succeed and it worked."
A silver medal is Phelan's reward for switching from Alpine skiing after competing at Sochi and she praised Serwa for teaching her the intricacies of ski cross.
"She is my best friend and is someone who has taught me everything about this sport when I switched from Alpine," the former slalom skier said.
"I love Alpine and I definitely miss it but I was made to be a ski cross racer and I proved that today."
BATTLE FOR BRONZE
As the Canadians raced away, a controversial battle was ensuing between Smith and Naesland for third.
After the race, both accused the other of using elbows to gain an unfair advantage, with Naesland distraught at having missed out on a medal.
"It was an unfair fight I think," said the Swede, who added that she would be seeking a conversation with Smith once she had cooled down.
"I did the same back also so I wasn't any better but she started it when I was on the way to passing her."
"She put her elbow out and stopped me."
Smith argued that it was just part of the sport.
"It is ski cross. We are not doing Alpine. For sure we pushed but she pushed, I pushed," the 25-year-old said.
"We are equal in this fight. We were both there and both did the same. It is what ski cross is."
Thompson, who qualified in first position coming into the heats, said she was pleased just to be competing at another Olympics after rupturing knee ligaments back in October.
"I am disappointed with how the race run but I am really proud that I was able to race here and compete for Canada," the Sochi gold medallist told reporters.
"That was an accomplishment in itself." (Reporting by Jack Tarrant; Editing by John O'Brien)