Thompson, from Whistler, B.C., won the skicross World Cup opener in Nakiska, Alta., last weekend but she narrowly missed out on qualifying for the women's final on Sunday when she finished third in a stacked semifinal. Only the top two advance.
West Vancouver's Georgia Simmerling and Kelsey Serwa, of Kelowna, B.C., were eliminated at the quarter-final stage, while the Canadian men were forced to watch from the sidelines after rapidly-changing course conditions saw many of the top racers eliminated during a wild qualification round on Saturday.
"It's disappointing we didn't have a podium because we set the bar pretty high but Marielle was able to keep the overall lead," said coach Willy Raine. "To come away with the results we had, with the girls competing together in the bottom bracket, it was a good day."
All four Canadian women qualified for Sunday's round of 32 but Calgary's Danielle Sundquist was third in her heat and finished 19th overall. Simmerling advanced from the same heat but was third in her quarter-final — behind Thompson and Swiss star Fanny Smith — to finish 10th overall.
Serwa, who is back in action following knee surgery, was skiing well Sunday but the start gate appeared to malfunction in her quarter-final and she was eliminated, finishing 15th overall.
An official complaint was lodged but the results were not changed.
"She will be able to keep training as she tries to peak for Sochi," said Raine of Serwa.
Thompson was her usual dominant self in the early rounds but made a small error in her semifinal and Norway's Marte Hoeie Gjefsen took full advantage to eliminate the Canadian by a matter of inches.
"She missed it by an arm's length at the finish line," Raine said. "She came out of it smiling and saying it was a great ski cross heat. There was passing and it was tight and everyone was close together."
Switzerland's Katrin Mueller won the women's final, with her teammate Sanna Leudi finishing second and French veteran Ophelie David taking third. Hoeie Gjefsen was fourth.
Sunday's results mean Thompson leads the women's ski cross World Cup standings with 145 points. David is second with 120 and Smith is third (116). France leads the Nations' Cup with 460 points, with Switzerland sitting second (405) and Canada third (298).
Austria's Andreas Matt won the men's final, with Sweden's Victor Oehling Norberg finishing second and France's Jean Frederic Chapuis taking third.