SINGAPORE: World No. 9 Kiki Bertens of the Netherlands advanced to the semi-final round of the WTA Finals in Singapore on Friday after Japan's Naomi Osaka was forced to retire due to injury.
World No. 4 Osaka, 21, pulled out after 47 minutes, reports Efe.
Trailing 3-6, Osaka called her coach Sascha Bajin for not feeling physically well, and as a result gave the 26-year-old Bertens a chance to win the tennis title.
"I saw her in the match before that she was struggling a little bit with the hamstring, and of course she was taped today, but I think in the beginning she was still okay," Bertens said in a post-match presser.
"It is never easy or never nice to win a match like this, but it is what it is. I will take it and I will take my rest, and I have some more recovery time for tomorrow," Bertens added.
This was their second career encounter after the 2016 match at the Mexican Open, where Osaka prevailed 6-4 6-2.
Bertens, the first from the Red group to reach the semi-finals, is set to next take on either Elina Svitolina of Ukraine or Karolina Pliskova of the Czech Republic on Saturday.