Top seed Angelique Kerber eased into the last four of the Volvo Open in Charleston after beating Irina-Camelia Begu 6-2, 6-3 on Friday.
The Australian Open champion had lost two of her three previous matches against the Romanian, who seemed to struggle for fitness following her tough, third round victory over Monica Puig the day before.
“I think I was mentally there. I was trying to focus on myself because it’s always tough to play against her,” said Kerber, who will play seventh-seeded American Sloane Stephens for a spot in the final of the claycourt event.
“Sometimes you lose your rhythm against her (Begu) so that’s what I was focusing on – just trying to go for it, move good on clay and just win the match because I remember the last match against her, I lost.”
After being thoroughly dismantled in the first set, Puig did fight back to an extent in the second stanza, hitting 23 winners in the process, but was pegged back by the 35 unforced errors she made.
“I’m feeling better and better on clay,” Kerber, who has to advance to the final to retain her world number two ranking, added.
Stephens, meanwhile, had her work cut out against 14th-seeded Daria Kasatkina, but eventually came through 6-1, 5-7, 7-5.
After the match, Stephens admitted that she had expected a tough match against her Russian opponent, who was playing in her first WTA Tour quarter-final on clay.
“She’s had some really good results, so I knew from the beginning that it was going to be a battle,” she said.
“The wind and we’re on clay court, (there) were a lot of factors, so I’m happy I stayed calm and played my game.”
Meanwhile, Russian qualifier Elena Vesnina booked her place in the last four with a 7-5, 6-4 victory over Germany’s Laura Siegemund.
Vesnina, who beat second-seeded Belinda Bencic in the second round, said she also struggled with the blistery conditions.
Her opponent in the semi-finals is fifth-seeded Italian Sara Errani, who beat Kazakhstan’s Yulia Putintseva 7-6 (7/2), 6-1.