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KANSAS CITY, Mo. (AP) Danny O'Shea tossed Tarah Kayne like he did countless times as they forged themselves as the best pair in skating.

This toss ended with Kayne face first on the ice instead of helping them get atop the leaderboard.

Kayne did not complete her throw triple lutz rotation and the right side of her face slammed the ice when O'Shea tossed her during the short program. Kayne and O'Shea's defense of their pairs title got off to a crushing start Thursday in the U.S. figure skating championships when the fall derailed their routine.

''This season has been really difficult for us,'' Kayne said. ''I don't think we were coming out here to match what we did. ''It's been a huge struggle all season to just maintain.''

Kayne was diagnosed with a tendon issue in one her knees that had an impact on training and competition for much of the past year.

Kayne and O'Shea, back to defend the title they won in St. Paul, Minnesota, sit in fifth place and will need plenty of help and a flawless performance in the free program on Saturday.

''It's not how you want to finish a program,'' O'Shea said. ''We'll pick ourselves up.''

Ashley Cain and Timothy LeDuc topped the board with 69.33 points in the first day of competition at the Sprint Center. Cain and LeDuc nailed their split triple twist, solo triple loops and throw triple flip to take the top spot.

Cain has not competed in pairs in nearly 4 1/2 years before she teamed with LeDuc in a May 2016 tryout. Not even a year later, the pair were in the thick of contention for their first U.S. national championship.

''The moment I took his hand, I didn't realize how much I missed pairs skating,'' Cain said. ''I had the biggest smile on my face and I could feel how happy I was; just skating with him, lifting me in the air.''

LeDuc took his own hiatus, nearly 2 1/2 years since he last competed in a major pairs event at the nationals in Boston.

''We're not afraid to sort of laugh and giggle especially through the difficult days or through mistakes,'' LeDuc said.

Haven Denney and Brandon Frazier were second with 65.39 points and Deanna Stellato-Dudek and Nathan Bartholomay were third with 65.39 points.

Denney has made a solid comeback since she tore her ACL, LCL and meniscus while practicing a throw in April 2015. They are still finding their groove after sitting out the 2015-16 season. Denney and Frazier won a silver medal at Skate America in October and hope for another podium finish this weekend.

''We try to keep everything together no matter if the score is amazing or just bad,'' Frazier said. ''But it was a respectable score. First time back, U.S. championships. We're just going to do what we can moving on.''

Kansas City was the site of the U.S. figure skating championships for the first time since 1985.

''I remember the audiences for ladies and men and dance being pretty substantial,'' U.S. Figure Skating President Sam Auxier said. ''One of the reasons that we came back to Kansas City was that we felt we could attract a pretty large audience to our sport. We'll be looking to see how many people attend our events and how well the community supports our skaters.''

The U.S. would love to find a breakthrough star out of this event that fans could follow through next year's Winter Games in South Korea. Tara Lipinski and Johnny Weir are wildly more popular in the broadcast booth than any of the skaters in the field.

Gracie Gold, a Missouri native competing later Thursday, and Ashley Wagner could help propel themselves into commercial stardom with gold in 2018.

''I think the American public really rallies behind skaters when they get on the platform and it attracts a larger audience and inspires more young ladies to try the sport,'' Auxier said. ''Clearly helping the ladies get to the podium is very critical for many aspects of U.S. figure skating.''