KIM CLIJSTERS is confident of producing the improved performance she feels is required to beat Vera Zvonareva in the Australian Open semi-finals today.

The Belgian overcame Agnieszka Radwanska 6-3 7-6 (7/4) yesterday to join Zvonareva in the last four and set up a rematch of last year’s US Open final which Clijsters won convincingly.

And with Russian Zvonareva gunning for revenge, third seed Clijsters knows she will have to improve if she wants to make it through to a meeting with either Li Na or Caroline Wozniacki.

She said: “Everything has to be better: serving, returning, the unforced errors.

“I feel like I am hanging in there, working hard to win my points.

“And sometimes that’s probably even more of an achievement than winning your matches very easily.’’