World number nine Garbine Muguruza was pushed all the way by Croatian challenger Donna Vekic, winning 7-6(7-4) 7-6(7-5).
Both athletes stuck with their strong serves, with Vekic hitting 10 over the two sets and Muguruza sending down 8. The difference was in fine margins, with Vekic nailing just two of her seven break points, with Muguruza grabbing the same from four chances.
That clinical edge saw her scrape by with two tie-breaks in her favour.
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Muguruza last won a Grand Slam event in 2017 when she won Wimbledon, a year after her French Open triumph.
She was able to reach the final of the Australian Open in 2020, but hinted at a return to better form at the Tokyo Olympics, where she reached the quarter-final stages.
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