Victoria Azarenka has booked a spot in the Madrid Open semi-finals by claiming a 3-6 6-3 6-3 win over Li Na.

Li managed to edge the opening set in Madrid after a well matched contest with the number one seed.

Both competitors were able to keep hold of their serve in the early stages, but it was the Chinese pro who forced the breakthrough and maintained her dominance to take the lead.

Azarenka composed herself for the second set and managed to take control. Her 30-year-old opponent continued to stay in contention but it wasn't enough as the Belarus pro snatched the second set to draw level.

Despite early dominance from Na, the world number one took charge of the third and final set by executing a number of powerful and precise shots on the blue clay court to launch herself into the semi-finals.

Azarenka will face either Agnieszka Radwanska or Varvara Lepchenko in the last four.