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.
Gadecki, Peers win Australian Open mixed doubles title
Australia's Olivia Gadecki and John Peers have become the first pair in 37 years to successfully defend the Australian Open mixed doubles title on Friday, defeating French duo Kristina Mladenovic and Manuel Guinard 4-6 6-3 10-8 in a thrilling final.
De Kock demolition leads S Africa to T20 series win over West Indies
Quinton de Kock has smashed a career-best 115 from 49 balls as South Africa easily chased down a victory target of 222 to beat West Indies by seven wickets on Thursday and secure the three-match Twenty20 International series 2-0 with a game to go.
Lyon top Europa League standings, Roma through to last eight
A 4-2 win at home against Greek side PAOK has secured Olympique Lyonnais a top finish in the Europa League standings as Italian side AS Roma scraped into eighth place and direct passage to the last 16 on the final league phase matchday on Thursday.
World Cup winner, Olympic champion Dunn announces retirement
Crystal Dunn, an Olympic champion and World Cup winner who made 160 appearances for the US women's national team, has announced her retirement from professional football on Thursday.
Pakistan win after all-rounder Ayub sinks Australia
Saim Ayub produced a brilliant all-round display to power Pakistan to a 22-run victory against a largely second-string Australia in the first Twenty20 international between the teams in Lahore on Thursday.
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The legendary Craig David joins The Kris Fade Show for an unforgettable chat!
The Rock and Chris Evans: A Christmas Surprise!
The super-star and multi-award-winning singer-songwriter, Jason Derulo is bringing the heat to Dubai.
From taking us down memory lane to a possible BAD BOYS 5 in Dubai?
