Britain’s Emma Raducano lost in straight sets in her first match since her sensational debut at Wimbledon last month.
The 18-year-old wildcard lost 6-3 6-2 to world number 51 Zhang Shuai in the Silicon Valley classic swap.
Her return to the WTA Tour in San Jose was followed by her run to the fourth round at Wimbledon, which He ended up in retirement.
“I am at the beginning of my journey, so I am grateful every opportunity I have because I am constantly learning,” she said.
Zhang, the 2019 Australian Open Grand Slam doubles champion, led 3-0 in the first set and quickly took a 4-0 lead in the second set at the night in the hard-court tournament.
Raducanu was broken four times in total, and while she got two break points for her veteran opponent early in the second set, she failed to capitalize.
“On the WTA tour, every match is going to be tough and there won’t be many good matches,” said Radocano.
“It’s my second WTA Tour tournament. What I’ve learned is how to try to handle someone when they’re playing really well and you feel like you’re not making too many mistakes but you’re always in the back.
“Rising to this level, I feel like she just dictated me. If I keep going like this at some point, it will pay off.”
Zhang hit 29 winners for a comfortable 82-minute win.