RUMFORD — One day behind schedule because of heavy rain Sunday night, the U.S. Cross Country Championships got underway at cold and blustery Black Mountain Tuesday morning with a welcoming ceremony and spectator-friendly freestyle sprints.

Torin Koos of Washington and Jessica Diggins of Minnesota successfully defended the sprint titles they won a year ago in Rumford.

Koos, 31, crossed the finish line of the championship heat with arms upraised Tuesday afternoon ahead of five other skiers from an initial field of 203 attempting to qualify for one of 30 quarterfinal berths on the 1.6-kilometer course.

“I’m back and I’m psyched about it,” said Koos, coming off a year that included shoulder surgery and mononucleosis. “Those were two major things, the two biggest things I’ve had to overcome.”

Dakota Blackhorse-von Jess of Oregon was second and Tyler Kornfield of Alaska third, just edging 2009 Bates graduate Sylvan Ellefson of Colorado.

Diggins, 20, snuck a peek over her shoulder at the line after her friend, roommate and training partner Jennie Bender took a spill in the homestretch of their 1.4-kilometer championship heat.

“To hear Jennie crash, that was really tough,” Diggins said. “You want to win because you’re fast, not when someone trips over their pole or whatever happened. I kind of wish we could do that over again.”

Bender managed to scramble to her feet in time to place in the money, but not before fellow Minnesotan Caitlin Gregg had surged into second place.

Prize money for men and women was $1,200 for first place, $600 for second and $300 for third.

Bender collapsed again after the finish, crying out in pain from a bruised tailbone.

“I’m actually not a big faller,” she said, still moving gingerly a few minutes after getting up. “But you’re going all out and you’re looking ahead. It’s when you’re screaming for the finish that you’re not really focusing quite as much on your exact movements, so that’s when stuff can happen.”

Diggins, Gregg and Bender are all teammates for CXC, which stands for Central Cross Country Ski Association. The only woman with a strong Maine connection to qualify for the 30-skier quarterfinals was Cape Elizabeth native Clare Egan, now racing for the Craftsbury Green Racing Project in Vermont.

Egan put forth the 19th-best qualifying time of 3 minutes, 14.1 seconds – only Diggins at 2:58.8 broke three minutes — and placed third in her heat, but was just behind the 12 women advancing to the semifinals because two other third-place finishers among the five heats had faster qualifying times and thus filled the two slots not taken by automatic qualifiers who finished first or second in their heats.

“Top 15 is good,” said Egan, who plans to race the 10K freestyle Thursday and the 20K classical with a mass start Friday as well as Sunday’s classical sprints. “I’m OK with that.”

Diggins won her quarterfinal and semifinal heat as well as turning in the fastest qualifying time. A year ago, she recovered from a fall in the championship heat, drafted off the five women ahead of her and sprinted to victory.

On Tuesday she experimented in the semifinals with drafting and trying to act as a sling-shot by using her momentum to take over the lead.

“But it started to get really messy,” she said. “There were people all over, poles all over. So (in the final) I decided to just get out front. It was risky and it was hard, leading into the wind, and it definitely sapped some energy. But I think it was definitely worth it to avoid any possible pole-ski tangles.”