MELBOURNE, Jan. 23 (UPI) -- Unseeded Serena Williams outlasted Shahar Peer in a three-set match Tuesday, earning a berth in the semifinals of the 2007 Australian Open.
Williams, who won the Australian Open in 2003 and 2005, will face 10th-seeded Nicole Vaidisova in the tournament semifinals.
Williams wasn't exactly sharp in beating Peer, the tournament's No. 16 seed. She had to come back from losing the first set and battled through 49 unforced errors and 13 situations in which she could have had her serve broken before winning 3-6, 6-2, 8-6 in more than 2 1/2 hours.
On the other hand, Peer didn't make the most of her chances, going 3-of-13 in break opportunities, including 2-for-10 in the final set.
Vaidisova had an easier time defeating Lucia Safarova 6-1, 6-4. It will be the second Grand Slam semifinal in the 17-year-old's career.
The other quarterfinals in the Australian Open's women's draw are set for Wednesday with top-seeded Maria Sharapova going against No. 12 Anna Chakvetadze and fourth-seeded Kim Clijsters playing No. 6 Martina Hingis.
