Evgenia Medvedeva finished fourth at the ISU Grand Prix in Grenoble and failed to qualify for December's Grand Prix Final in Vancouver.
After finishing third in the short program on Friday the Russian struggled again in her free skate, nearly falling twice.
Her fourth-place finish with 192.81 meant she missed the podium for the first time in her senior career.
Japan's 16-year-old Rika Kihira won the competition with 205.92, with compatriot Mai Mihara (202.81) in second and American Bradie Tennell in third (197.78).
"What happened during the free skate, honestly I don’t want to call it horrible once again... it’s 100% a mental issue, I admit my mistakes, I am not someone who denies them, said Medvedeva.
While she was clearly showing nerves, the surprise winner from Japan landed a triple Axel to stun the crowd in her senior international debut season.
"Until last year, I couldn't really show my strengths in competitions. I've learned from past mistakes, built up experience, and remember when things didn't work and I lost focus," Kihira said.
"I'm determined not to repeat these mistakes. At the same time I'm very grateful to be able to compete in major events like this one, so I have a sense of appreciation, and I keep my determination."
Joining Kihira as ladies qualifiers for the ISU Grand Prix Final are Olympic champion Alina Zagitova, Elizaveta Tuktamysheva, Satoko Miyahara, Sofia Samodurova and Kaori Sakamoto.
Now what Evgenia?
Medvedeva's troubles continued in Grenoble. The two-time World Champion who had not lost for two years from 2015 to 2017, has now not won in more than a year.
She will not be at the Grand Prix Final for a second year in a row after missing last year's event with a broken bone in her foot.
"I just wanted it so much, I pushed too hard, I let my mind flow, I just didn’t think. Yes, I gave up in this program and this is the moment that we will be working on."
Nathan Chen's change in fortunes
This was in stark contrast to Nathan Chen in the men's event, who rallied from Day 1 to qualify for the finals in Canada.
The American began Day 2 in France in third place, having fallen in his short program.
But he bounced right back with a 184.64 clean run in the free skate to secure first place with 271.58 overall.
Compatriot Jason Brown took second place overall with 256.33, while third place went to Russia's Alexander Samarin (247.09).
Chen joins Yuzuru Hanyu, Shoma Uno, Michal Brezina, Sergei Voronov and Cha Jun-hwan in the finals.
"I'm still not at the level I should be technically. There's a lot of work to be done, but whatever I did, I did. I am pretty satisfied", said Chen.
"The goal is to keep on improving, keep on adding more (to his program), keep on developing on what I currently have. It's a confidence booster knowing that I continue to add more as the season progresses.
"What I did today was the maximum of my capabilities as of right now and we'll see about the future."
Short program shortcomings
Medvedeva and Chen both struggled to find their best form in the short program.
The Russian scored 67.55 to trail first-placed Mihara from Japan (67.95) and her compatriot Rika Kihira (67.64) in second.
She needed victory in her free skate to be guaranteed a spot at the Grand Prix Final in December, but fell well short.
Meanwhile Chen hit the ice on Friday attempting a quadruple flip, which left Brown in top spot going into the free skate.
Sochi medallist Brown scored an impressive 96.41 in a clean, quad-less program, which placed him ahead of second-placed Samarin.
Chen's performance required a fourth-place finish or better to guarantee qualification for the finals.
And he delivered.
Chen landed three quadruple jumps in a clean free skate to become the first man to win five straight Grand Prix starts in more than a decade.
Hanyu awaits Chen in Vancouver
A mouth-watering showdown with two-time Olympic champion Hanyu now awaits Chen in the Grand Prix Final if the Japanese is fit.
Hanyu injured his ankle at the Rostelecom Cup in Moscow last week.
"It's always a great opportunity to compete against the top of the skating world, a great honour to watch him (Hanyu) from afar and motivate me, it's disappointing if he won't be at the Grand Prix Final," Chen said.
"Whoever's at the GP Final won't matter because it's dependent of what I do myself.
"I really look forward to competing against him at some point this year further along."
Chen has been balancing skating with his studies as a Yale student, but seems to be handling both with aplomb.
The freshman won the Skate America event last month.