The 19-year-old Australian, currently sitting at a season-high ranking of No.36, defeated Russian world No.19 Diana Shnaider 7-5 6-1 at the WTA Tour event in Beijing.
It sets up a round-of-16 clash against Britain's Sonay Kartal, who enjoyed a 6-3 6-0 victory over another Aussie in Daria Kasatkina.
Joint broke in just the second game of her contest, but immediately handed it back. The match went with serve until the 12th game, and after blowing four set points the teenager took the first set.
She returned with vigour and broke three more times in the second set to complete the job in one hour 25 minutes.
It took just 63 minutes though for the third Australian in action on Saturday to be eliminated.
World No.94 Ajla Tomljanovic was swept aside by American Jessica Pegula.
The 2024 US Open semi-finalist and tournament fifth seed won 6-0 6-3 and next faces either Emma Raducanu or Cristina Bucsa.
Earlier on Saturday, Wimbledon champion Iga Swiatek defeated Yuan Yue 6-0 6-3 to advance to the third round and create some history.
The WTA said the Pole became the first player to register 25 or more wins at WTA-1000 events for three consecutive seasons.
The top seed, who won last week's Korea Open in Seoul, has also won the French Open four times and the US Open once among her six grand slam singles titles.
Fourth-seeded Russian Mirra Andreeva beat Chinese player Zhu Lin 6-2 6-2, and Emma Navarro defeated Elena-Gabriel Ruse 6-3 7-6 (7-0).
Japan's Naomi Osaka won the opening set of her second-round match before Aliaksandra Sasnovich, of Belarus, rallied to win 1-6 6-4 6-2.
With the AP.
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