BEIJING, China - No.2 seed Caroline Wozniacki progressed to her first semifinal since Eastbourne in June with a 6-2, 6-3 defeat of qualifier Katerina Siniakova at the China Open.

The win maintained the former World No.1's immaculate record against her opponent on hard courts, adding to two previous straight-set triumphs in Wuhan in 2016 and Indian Wells last year, and avenged a loss in their most recent meeting in the 2017 Bastad final on clay. It also marks a timely return to form for Wozniacki, who had not won consecutive matches in six tournaments over the last three months before touching down in Beijing.

The key for the Australian Open champion was her impregnable serving. Maintaining a first serve percentage of 72%, Wozniacki won an astonishing 93% of those points in the first set, and overall would drop 10 points behind her delivery - in the first set, just two.

The 28-year-old would also be watertight off the ground, leaking a measly seven unforced errors. Playing well within herself, Wozniacki's strategy was to move her opponent relentlessly around the court - an extremely effective approach against Siniakova, whose non-stop schedule following her Wuhan quarterfinal run, also as a qualifier, meant that the Czech No.4 was playing her 12th match in the past fortnight.

Siniakova's scalps over her two weeks in China have included three seeded players - Caroline Garcia and Garbiñe Muguruza in Wuhan, and Kiki Bertens in the previous round here in Beijing - but the World No.40 offered up too many tired errors to score another upset today. Though there were flashes of creativity and brilliance - a flurry of perfectly constructed points to hold for the first time, a sudden serve-and-volley play to save a first set point - Siniakova could not sustain the point-in, point-out accuracy needed to consistently hit through the indefatigable Wozniacki.

Three forehand errors and a double fault conceded a break off the bat, and though Siniakova briefly hit peak form to turn the final game of the first set into a mini-tussle, another forehand would sail wide for the Dane to capture the opening act on her third opportunity. Ultimately, the 22-year-old would be sunk by a total of 28 unforced errors.

The Roland Garros and Wimbledon doubles champion would show off her proficiency in the forecourt on a number of occasions as she sought to cling on to the scoreboard - but Wozniacki would win the best point of the match to break in the second game, finally hitting through some breathtaking Siniakova defence with a drive volley putaway.

Ultimately, the second set would follow an identical pattern to the first: an opening break for Wozniacki followed by a series of holds before the 2010 champion sealed it with a second break. This time, the defending WTA Finals victor set up two match points with a magnificent pass - and although Siniakova fended off one with another neat volley winner, a third double fault from the Czech racket ended the match after one hour and seven minutes.

Back in her fifth semifinal of the season, Wozniacki will seek to keep her renaissance going against one of the two most in-form players of recent months: either Aryna Sabalenka or Wang Qiang awaits in the semifinals.