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.
Benzema moves to Al-Hilal following Al-Ittihad departure
Karim Benzema has joined Al-Hilal, the Saudi Pro League leaders announced on Monday, following the termination of his contract with Al-Ittihad.
Pakistan to boycott T20 World Cup group match against India
Pakistan will boycott their February 15 match of the Twenty20 World Cup against arch-rivals India in Colombo, the Pakistan government said on Sunday while approving the team's participation in the global showpiece.
Dubai Basketball rounds off Family Day with another ABA League win
Dubai Basketball has marked its growing popularity in the UAE by hosting its first Family Day on Sunday, and marked celebrations with another ABA League victory against Bosnian side Igokea at Coca-Cola Arena.
Man City and Villa slip up in title race, Man Utd win again
Manchester City and Aston Villa both slipped up in their pursuit of Premier League leaders Arsenal on Sunday with City drawing 2-2 at Tottenham Hotspur and Villa slumping to defeat at home to 10-man Brentford.
Justin Rose sails to wire-to-wire Farmers victory
England's Justin Rose won the Farmers Insurance Open for the second time by shooting 2-under-par 70 on Sunday in San Diego.
