Russian tennis player Karen Khachanov on Thursday reached the Halle Open quarter - finals after the withdrawal of Japan's Kei Nishikori due to injury.
After receiving medical treatment on the court to treat a back injury, the World No. 9 Japanese player opted to pull out after 34 minutes, with the score at 3 - 2, reports Efe.
The 21 - year - old Russian now advances to the quarter - finals to play against the winner of the match between his compatriots Mikhail Youzhny and Andrey Rublev.