Home ice was kind to Marissa Castelli and Simon Shnapir.
The reigning national champions who train in Boston led after the pairs short program at the U.S. Figure Skating Championships at TD Garden on Thursday.
They beat their personal best by more than 10 points, scoring 73.13 points skating to Santana for a cushion of 6.63.
“I was in shock at first; I was not expecting that,” Castelli said, according to The Associated Press. “I like to try to calculate it in my head. I would have been happy with 66 or 67, so it was just insane.”
Castelli and Shnapir are in the driver’s seat for one of two U.S. Olympic pairs berths. It marked confirmation that Castelli and Shnapir are the top U.S. pairs team. Their title last year came with an asterisk as the previous U.S. champions were absent due to injury.
Their closest competition Thursday was a bit of a surprise — reigning U.S. bronze medalists Felicia Zhang and Nathan Bartholomay followed by DeeDee Leng and Timothy LeDuc, who were ninth last year.
The pairs free skate starts at 2:45 p.m. on Saturday (NBC, NBC Sports Live Extra, 3-6 p.m.). The two U.S. Olympic pairs teams, based largely but not solely off the final standings, will be announced Sunday around noon.
Castelli and Shnapir’s short program included clean side-by-side triple Salchows and a strong throw triple Salchow.
The biggest eye opener was Leng and LeDuc, who followed flawed efforts from more accomplished couples by posting a cleaner 66.40-point performance.
2012 U.S. champions Caydee Denney and John Coughlin, he of the incredible back tattoo, were fourth at 65.40. Denney, a 2010 Olympian at 16 with a different partner, doubled a planned triple toe loop and had trouble with her landing on a throw triple flip.
“I wish we would have performed a little bit better — a lot better,” Denney told reporters. “I think right now all we can do is trust ourselves and really just move on and throw everything into Saturday’s performance and try to do the best that we can.”
2013 U.S. silver medalists Alexa Scimeca and Christopher Knierim were fifth at 64.68. They fell, nearly in unison, on side-by-side triple Salchows.
Unpredictable results are common in U.S. pairs, where few strong couples stay together for more than a few years and the previous five years produced five different U.S. champions.
In fact, the last pair to win back-to-back titles, Keauna McLaughlin and Rockne Brubaker, won their golds in 2008 and 2009 and then failed to make the 2010 U.S. Olympic Team.
No U.S. pair has won an Olympic medal since 1988. That does not figure to change in Sochi. The favorites will be Russians, Germans, Chinese and Canadians.
Pairs Short Program
1. Marissa Castelli/Simon Shnapir — 73.13
2. Felicia Zhang/Nathan Bartholomay — 66.50
3. DeeDee Leng/Timothy LeDuc — 66.40
4. Caydee Denney/John Coughlin — 65.40
5. Alexa Scimeca/Christopher Knierim — 64.68