Beijing - Second seed Simona Halep overcame stubborn resistance from Andrea Petkovic to make the quarter-finals of the China Open on Thursday, while Tomas Berdych powered into the last eight of the men's competition.
Halep defeated her German opponent 7-6 (7/4), 5-7, 7-6 (7/1) as she dominated at the tie break in the first and third set of the two hour 35 minute epic in Beijing.
The Romanian world number two had difficulty coping with the serve of her opponent, who is ranked at number 17 by the WTA, and also lost her own serve nine times during the closely-fought match.
It has been a remarkable 2014 for Halep, who started the year ranked 11th but leapt to second after winning WTA titles in Bucharest and Doha, as well as reaching the final at Roland Garros.
But the 23-year-old suffered a disappointing third round exit at the US Open last month and tumbled in her opening match at the Wuhan Open last week.
Meanwhile in Beijing, seventh seed Angelique Kerber suffered an agonising defeat to Russian Svetlana Kuznetsova 2-6, 6-4, 6-3.
Kerber is desperate for points as she is seeking a place at the WTA Finals in Singapore, the end-of-season finale involving the world's top eight women players.
Russian Ekaterina Makarova is another player whose hopes of making Singapore were potentially dashed, as the 12th seed in Beijing crashed out to Roberta Vinci 6-1, 0-6, 7-5.
The Italian will meet Petra Kvitova in her quarter final match, after the world number three made it through without having to play on Thursday.
The much-anticipated duel between Kvitova and Venus Williams failed to happen when the American withdrew with a "viral illness".
The pair met in a third round match at Wimbledon which finished 5-7, 7-6(2), 7-5 in favour of Kvitova, the eventual winner of the tournament. It was widely regarded as the match of the championships.
In the men's competition, Czech world number six Berdych helped his cause to qualify for next month's ATP World Tour Finals in Great Britain when he made the quarter-finals.
The champion in Beijing in 2011 currently holds the eighth position in the race for London, the final berth for the end of season tournament involving the world's top eight players.
He beat Viktor Troicki in straight sets in his second round match, saving two break points in the third game before breaking his opponent and clinching the opener 6-3.
The pair traded serves midway through the second set before Berdych took a two-game lead which he held to finish the match 6-3, 6-4.
Berdych made the semi-finals in Beijing last year and will have to beat American John Isner to achieve the same feat this year.
Elsewhere in the men's competition, Slovak Martin Klizan defeated Ernests Gulbis when the Latvian retired with a shoulder injury with the scores at 6-2, 3-0.
The $5.4 million China Open will reach its climax on October 5.