Olympic champion Zheng Qinwen finds mojo to reach Tokyo semis
The top seed beat Canada's Leylah Fernandez 6-0, 1-6, 6-3 to set up a final-four showdown with Russia's number six seed Diana Shnaider.
Zheng became the first Chinese player to win Olympic singles tennis gold when she triumphed in Paris this summer.
She said her "life changed" as a result and she "couldn't walk on the street" when she returned to play in China last month.
The 22-year-old is playing in a more sedate environment at the Pan Pacific Open in the Japanese capital and said it was "tough to find motivation".
"Especially after I finished in China because I got big expectations, a lot of stress, a lot of pressure there to play good in the Chinese events," she said.
"I already did one mistake after Australia, I lost motivation and lost a couple of matches I should not lose," she said, referring to reaching the Australian Open final in January.
"This time my team is trying to explain to me how important it is to keep the motivation up. If you are there on court, you need to fight 100 percent."
Zheng looked set for a comfortable evening's work when she took the first set without dropping a game against Fernandez.
She said that her concentration dropped in the second set, but she refocused to reach her sixth semi-final of a breakout year.
"I'm happy I get (had) two matches (so far) here because honestly my motivation wasn't that high," she said.
"But I'm still able to push myself and get the match."
Zheng arrived in Tokyo after losing to Aryna Sabalenka in the final of the Wuhan Open. Sabalenka also beat her in the final in Melbourne.
Before Wuhan, Zheng played at the China Open in Beijing, where she says the impact of her Olympic gold finally began to sink in.
"When I won the gold medal, honestly I didn't feel my life had changed until I went back to China," she said.
Zheng will face Shnaider for the first time in Saturday's semi-finals. The Russian advanced with a walkover when Japanese quarter-final opponent Sayaka Ishii withdrew injured.
Britain's number nine seed Katie Boulter will face American wild card Sofia Kenin in the other semi-final.
Boulter beat Canada's Bianca Andreescu 6-2, 6-1 while Kenin beat Russia's number three seed Daria Kasatkina 6-3, 6-4.