American Stephens entered the tournament seeded 24th after enjoying a confidence boost from winning her second WTA title at Auckland in the lead-up but racked up 36 unforced errors in a meek 6-3 6-3 capitulation at Hisense Arena.
China has longed for a new force in women's tennis following the retirement of two-time grand slam champion Li Na in 2014 and 102nd-ranked Wang's victory offered an encouraging glimpse of the next generation's potential.
"She's a good player and I watched her match before so I know her a little bit and I just tried," Wang, her country's number two after Zheng Saisai and one of five Chinese women in the draw, told reporters in halting English.
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"It was my first time at Hisense so I was a little bit nervous."
Former world number two Li remains fondly welcomed as an ambassador at the year's first grand slam, where she won the 2014 title in her third trip to the final and gave a hilarious winner's speech thanking her agent for "making her rich" and her hen-pecked husband for "fixing the drinks".
Li mixed with the Chinese entrants at a pre-tournament function but Wang felt too awkward to approach Asia's first grand slam singles champion, an icon of the sport in her country.
NEGATIVE ATTENTION
"I didn't because there were a lot of people there and actually we're not that familiar," the 24-year-old told reporters in Mandarin.
"I'd feel strange walking up to her and asking her 'Miss, how should I play tomorrow?'"
Stephens broke into the tennis spotlight at the Australian Open three years ago when she upset Serena Williams as a care-free 19-year-old on an electrifying run to the semi-finals.
She followed that up with a quarter-final appearance at Wimbledon the same year but has not surpassed the fourth round at a grand slam since.
America's disappointment at her failure to progress has seen some withering media critiques in the ensuing years and Stephens said she had struggled with the negative attention in the past.
"After Auckland everyone was like 'oh, we can support Sloane again because she's playing good and she's looking good and we need to get back on that bandwagon because we kind of abandoned her'," she said.
"And then you lose and they go back to 'she doesn't work hard, she's not committed, she doesn't love the game'.
"For me, I'm never going to win... I'm human so I have bad days."
(Editing by John O'Brien)
