Calgary's Leman was eliminated in the men's semifinal while reigning world champion Serwa, from Kelowna, B.C., dropped out after finishing third in the women's quarter-finals.
"It's disappointing any time we have a home advantage and we don't get someone on the podium,” said Leman, who was second in the overall men's rankings last season. "My starts were just a little off today. Sixth is still a pretty decent result. Any time you get to the semifinals it's not too bad. But I wanted to be on the podium really bad today. I wanted to win."
Swiss racer Armin Niederer won the men's final ahead of teammate Alex Fiva, while Austria's Anton Grimus was third. Canadian newcomers Louis-Pierre Helie of Berthierville, Que., and Kelowna's Ian Deans were 25th and 27th, respectively
In the women's event, Swiss ace Fanny Smith won a tight final ahead of French veteran Ophelie David. Sweden's Anna Holmlund was third and Swiss star Katrin Mueller was fourth. Georgia Simmerling of West Vancouver, B.C., finished 16th.
Serwa and Simmerling were both eliminated from a stacked quarter-final heat that also included Holmlund and Mueller.
Sitting second, Serwa looked poised to advance until Mueller appeared to catch an edge and veer towards the duo. Mueller moved into first place and Holmlund edged Serwa in a photo-finish at the line.
"Anna saw her and stood up and veered into me and I had nowhere to go except to stand up. It's the difference between a finger and that's racing — I have no regrets,” said Serwa. "I'm really happy with my performance today and now the results will come slowly.
"My goal is to just get more confident and, you know, focus on the start sequence and just be closer to the girls . . . I literally skied across a girl's skis so I feel like I'm back and I'm ready to win the next race."