Emma Raducanu was forced to retire from her Korea Open quarter-final against Daria Kasatkina on Saturday due to a foot injury. The Brit had been troubled by the same issue in her win over Yue Yuan in the previous round, and it proved too painful to overcome in Seoul.

Kasatkina dominated the first set 6-1 and Raducanu opted not to come back out for the second after just over 30 minutes of action. The Russian advanced to the semi-finals in South Korea but her class shone through when she began her post-match interview with a show of sympathy for her frustrated opponent.

"First of all, I feel sorry for Emma for retiring during the match," Kasatkina said. "It's a pity to get injured, especially in the deeper stages on the tournament. I wish her a speedy recovery to get ready for the next tournament. I know that this swing is important for her."

Though Raducanu shook Kasatkina's hand with a smile on her face, retirement through injury brings a bitter end to what had otherwise been a promising run to the last eight.

The 21-year-old was devastated to crash out in the first round of the US Open last month and she successfully bounced back with wins over two top-50 players at her very next tournament. Peyton Stearns and Yuan were both dispatched in straight sets at the Korea Open before Kasatkina extended her flawless head-to-head record against Raducanu to 3-0.

Raducanu received medical treatment during her victory over Yuan but there was optimism she would be fresh by the time she faced Kasatkina, given that rainy conditions in Seoul pushed the quarter-finals back from Friday to Saturday.

As the top seed and the world No 13, Kasatkina would have posed a stiff test even for a fully-fit Raducanu. She hit the former US Open champion with four aces, hit 11 winners and converted three of her four break points in their solitary quarter-final set.

Raducanu converted a break point of her own to tie things up at 1-1 after being broken in the very first game of the match, but things started to unravel from then on, and she received medical treatment on her left foot at 4-1 down.

It remains to be seen whether Raducanu is able to recover in time for the China Open on Wednesday or she opts to sit out the WTA 1000 event for fear of aggravating the issue.