Caroline Wozniacki secured her place in the Japan Open semi-finals with a hard fought victory over Aleksandra Wozniak.

After stumbling in the second set tie-break, Denmark's Wozniacki prevailed with a 6-2 6-7 (1/7) 6-2 win.

The Dane appeared to be on her way to another comfortable win when she took the first set, but her near-namesake fought back taking a tense second by storming through the tie-breaker.

But Wozniacki upped her game in the final set, finding rhythm on serve and breaking twice to finish the match off with relative ease.

Next up for Wozniacki is third-seeded Australian Samantha Stosur, who had an easier day with a 6-1 6-3 win over Jill Craybas of the United States.

The other semi-final will see India's Samia Mirza face Italian fourth seed Francesca Schiavone after both players advanced courtesy of injuries to their quarter-final opponents.

Unseeded Mirza was 6-4 2-0 up against second seed Marion Bartoli when the Frenchwoman had to withdraw with a shoulder injury, while Schiavone was handed a walkover with Melinda Czink unable to take the court because of a foot problem.