The World number one beat Croatian Donna Vekic 6-3 4-6 7-6 (7-4) at the Porsche Tennis Grand Prix.
Osaka will now face Anett Kontaveit, who was able to progress after Victoria Azarenka retired.
Petra Kvitova will face Kiki Bertens in the other semi-final.
Sri Lanka fight back through spinners but India 460-9
Sri Lanka struck back through spinners but Devdutt Padikkal's elegant 167 powered India to a commanding 460-9 in the rain-plagued opening test in Galle on Sunday.
Bangladesh claim first test win in Australia as Green ton in vain
Bangladesh has chased down 57 runs to complete a landmark nine-wicket victory over Australia in the series-opener in Darwin on Sunday in one of test cricket's greatest upsets.
Djokovic falls in Cincinnati heat in first match since Wimbledon
Thiago Agustin Tirante has rallied past Novak Djokovic 2-6 6-4 6-4 at the Cincinnati Open on Saturday, as the Serbian struggled in the heat and required a medical timeout in a disappointing US Open tune-up.
Islam Makhachev wins record 17th straight fight at UFC 330
Islam Makhachev (29-1 MMA) has successfully defended his UFC welterweight championship Saturday night, defeating Ireland's Ian Machado Garry (17-2 MMA) via unanimous decision (49-46, 49-46, 48-47) while also setting an impressive record in the main event of UFC 330 in Philadelphia.
Germany's Liebmann smashes 1500m world record
Germany's Johannes Liebmann has smashed the world record for the men's 1500 metres at the European Aquatics Championships on Saturday, knocking almost four seconds off the previous record in a dominant display.
