Emma Raducanu has retired from the Korea Open quarter-finals with an apparent left foot injury after losing the first set 6-1 to top seed Daria Kasatkina.
The Briton was looking to reach her first semi-final above WTA 250 level since winning the 2021 US Open.
Kasatkina had not dropped a set to Raducanu in two previous meetings, including a 6-2, 6-2 win in the grass-court quarter-finals at Eastbourne three months ago.
Raducanu had advanced to the quarter-finals of the Korea Open after beating Yue Yuan.
“I feel sorry for Emma… it’s easy to get injured, especially in the later stages of these tournaments,” Kasatkina said. “I wish her a speedy recovery.”
The winner of the clash between fourth seed Diana Shnaider and fifth seed Marta Kostyuk will face Kasatkina in the semi-finals later on Saturday after rain cancelled Friday’s play in Seoul.
Earlier in the day, Brazilian third seed Beatriz Haddad Maia eliminated lucky loser Polina Kudermetova 6-2, 6-1 to set up a semifinal clash with Veronika Kudermetova, who beat Viktoriya Tomova 7-5, 6-3.