Shahar Pe'er recorded one of the biggest wins of her career late Saturday night, defeating world No. 15 Nicole Vaidisova 6-4, 3-6, 7-6 (5) to advance to the fourth round of the US Open. Pe'er (19) and Vaidisova both struggled for consistency throughout the two hour and 32 minute long encounter, hitting a combined 97 unforced errors. The 20-year-old Israeli, however, was the slightly more composed player in the third set tiebreaker and clinched the error-ridden match on her fourth match point. "I defended very well throughout the match and attacked when I needed too," Pe'er said after booking her place in the fourth round at Flushing Meadows for a second straight year. "I returned her first serves well and tried to attack her second serve whenever I had a chance. It was a long match with long points, but I'm in good shape." Pe'er's next opponent is Polish teenager Agnieszka Radwanska who defeated No. 2 seed Maria Sharapova 6-4, 1-6, 6-2. The Pole was extremely impressive against the defending champion, but Pe'er will nevertheless like her chances against the inexperienced 18-year-old who will be playing in the fourth round of a Grand Slam tournament for just the second time in her career. "Radwanska is a very good player, who has made a big leap forward in the last year," Pe'er said. "We mustn't forget who she beat in her last match. It's going to be a very tough encounter." Pe'er, who was making her debut under the bright lights of the Arthur Ashe Stadium on Saturday, struggled at the beginning of the match, allowing Vaidisova to open a 3-0 lead. The Israeli broke back against the 18-year-old Czech and held serve in the sixth game to tie the score at 3-3. In the ninth game of the set Pe'er broke her opponents serve for the second time and held serve in the subsequent game to wrap-up the first set. Vaidisova opened a 3-0 advantage in the second set, but once more the Israeli fought back and won the next three games to tie the score. In the eighth game of the set the Czech broke to open a commanding 5-3 lead and tied the match by claiming the following game. After splitting the first six games of the third set, Pe'er surged ahead and took the next two games, reaching a match point in the ninth game. The Israeli, however, lost three straight points and Vaidisova went on to tie the set by holding serve in the 10th game. Pe'er squandered another match point in the 12th game and the match had to be decided on a tiebreak. Pe'er and Vaidisova split the first six points of the breaker, but the Israeli opened a 6-4 lead with a superb backhand. A Pe'er miss-hit brought Vaidisova back within one point, but in the next point the Czech hit a forehand into the net and Pe'er screamed with relief after booking her place in the fourth round. "I'm glad I won such an important match at such an arena," Pe'er said. "She played very well in the first and second match points and returned all my shots in the third. In the fourth match point, however, she finally made a mistake." Ram, Erlich crash out Andy Ram and Yoni Erlich failed to reach the last eight of a Grand Slam tournament for an eight consecutive time on Sunday night, losing 7-5, 7-6 (4) to Simon Aspelin and Julian Knowle. The Israelis, who were seeded eighth in the tournament, were hoping to end their poor major run and repeat their 2005 US Open performance that saw the duo advance to the quarterfinals. Ram and Erlich, however, never came close to progressing and were edged in both sets by the No. 10 seeds. Aspelin and Knowle broke the Israelis in the 11th game of the first set and clinched the set in the following game on their fourth match point. Both doubles duos held serve throughout the second set and the winner had to be decided on a tiebreak. Aspelin and Knowle raced to a 5-2 lead and would stay ahead for the remainder of the breaker to book their place in the quarterfinals. Ram and Erlich faced each other in the second round of the mixed doubles tournament late Sunday night, with Ram partnering Nathalie Dechy and Erlich playing with Chia-Jung Chuang.