April 6 (Reuters) - American Madison Keys claimed a marathon 6-2 6-7(5) 7-5 win over compatriot Bernarda Pera to advance to the semi-finals of the Charleston Open on Friday, keeping her dreams of a maiden title at the Family Circle Tennis Center alive.
Keys, who was a finalist in Charleston three years ago, struggled at times against the tactics of the left-handed Pera, who worked to keep the ball away from her opponent’s powerful forehand during the 134-minute contest.
However, Keys was able to rely on her biggest weapon, her punishing serve, to keep the pressure on Pera, winning 72 percent of her first service points on a sun-soaked day in South Carolina.
“I had to be proud of what I did on the court today,” said Keys, a finalist at last year’s U.S. Open. “And I knew if I didn’t leave it all out there, I would have been really mad at myself later.”
The seventh-seeded Keys will face Kiki Bertens, who overcame leg pain to dispatch France’s Alize Cornet 6-2 7-5 in their evening quarter-finals match.
Leading 5-4 in the second set, the Dutch 12th seed called for a trainer to come out to help stretch her left leg, which she had reached for several times in the previous game.
Cornet took advantage of her hobbled opponent in the next game to win her first break of the contest but Bertens was able to break back immediately and ran down a drop shot on match point to punch her ticket to the semi-finals.
In other quarter-finals action, Anastasija Sevastova used her all-court game to crush Kristyna Pliskova 6-4 6-0 to advance to the semi-finals, where she will play German Julia Goerges.
The Latvian eighth seed won 77 percent of her first service points against the Czech and never faced a break point in the match that lasted a little less than an hour.
The fifth-seeded Goerges fired nine aces en route to a 6-4 6-3 win over defending champion Daria Kasatkina and set up a battle with Sevastova.
The contest will offer a shot at revenge for Auckland Open champion Goerges, who Sevastova defeated in straight sets in the third round at Indian Wells last month.
Despite that loss, Goerges still holds the edge in the pair’s head-to-head meetings, having won four of their six career matches. (Reporting by Rory Carroll; Editing by John O’Brien)