Defending champion Kaori Sakamoto placed second, just over half a point behind Bradie Tennell of the United States, after the women's short program at the Four Continents Figure Skating Championships on Thursday.
American Mariah Bell is third and Sakamoto's compatriot Rika Kihira fifth heading into Friday's free skate at Honda Center.
"I ignore all the hype before I skate," Tennell said. "I think it is great to have two American ladies in the top three. Being in the lead doesn't change what I have to do. It's not a big thing over my head."
Sakamoto landed all her jumps, including a triple flip/triple toe loop, in her performance to "From My First Moment." She scored a season-high 73.36 points to position herself just behind Tennell, who earned 73.91, also her best score this season.
"I was a nervous wreck but I easily jumped my jumps," said the 18-year-old Sakamoto, who earned the highest program component scores of the segment with 33.38.
"I thought I did something stupid again when I wobbled during my last spin. I hope I'll be able to do what I have to (in the free program)," she said.
Bell was pleased with her performance.
"I think it was better today, it felt like it had better flow and it was better than the ones I did in the Grand Prix series this past fall," Bell said.
Kihira failed to land her 3½-rotation triple axel and finished with a score of 68.85, while 2017 Four Continents champion Mai Mihara under-rotated her opening triple lutz/triple toe, and placed eighth with 65.15 points.
Kihira, who won the 2018-19 Grand Prix Final, is dealing with an injury to her left ring finger. She skated with tape on the finger, which was partially dislocated.
"I decided to jump the triple axel after the six-minute (official) practice, but I lacked speed. I hope to practice a lot more and include at least one in my (free) program for sure," Kihira said.
Later on Thursday, American Vincent Zhou scored 100.18 points to take the lead after the men's short program, followed by South Korea's Cha Jun-hwan (97.33) and defending champion Jin Boyang of China (92.17).
Olympic and world silver medalist Shoma Uno finished fourth with 91.76 for Japan's best result, while Keiji Tanaka (83.93) is in seventh place and Kazuki Tomono (74.16) is 12th.
American Tomoki Hiwatashi is in ninth place with 76.95.
"This is a good experience. It does add some pressure, but regardless of my position, my approach to the free skate should remain the same," Zhou said.
Jin, who beat Uno for gold at last year's Four Continents, failed to complete a quad lutz. Uno stepped out of his opening quad toe loop and triple salchow/triple toe loop combination.
Uno is looking for his first Four Continents title, but he only resumed training a week ago after suffering repeated ankle sprains.
"I didn't practice enough to say I'm disappointed so I don't have the right to say that. The only thing I have to do now is give it my all. I'm not going to play it safe, I'm skating aggressively (in the long program)," Uno said.
The men's field is missing two of the biggest names —Yuzuru Hanyu and Nathan Chen. Two-time Olympic gold medalist Hanyu is recovering from a right ankle injury and reigning world champion Chen opted to focus on his studies as a freshman at Yale University.
