<p>The world number one and top seed worked past midnight and into Wednesday for his victory, which set him up for a match against compatriot Fernando Verdasco.<br /><br />The eighth seed beat David Ferrer 5-7, 6-7 (8-10), 6-3, 3-6, 7-6 (7-4) on a day five Spaniards battled for advancement.<br /><br />Nadal and Verdasco are to play the first Spaniard-vs-Spaniard quarter-final at the Open. "Fernando is a complete player, one of the best," Nadal said after coming through with only two unforced errors in the third set. "He has all these shots and had an amazing comeback today."<br /><br />Swiss Stanislas Wawrinka dealt a blow to American tennis as he left the host nation without a men's quarter-finalist for the second year in a row after a 7-6 (11-9), 6-7 (5-7), 7-5, 4-6, 6-4 defeat of Sam Querrey.</p>.<p>Wawrinka, coached by Roger Federer's one-time mentor Peter Lundgren, reached the last eight of a Grand Slam for the first time in his career.<br /><br />It was a marathon lasting just over four and a half hours with plot twists galore. Querrey saved a match point in the final game as Wawrinka was unable to smash out of a lob, but an error into the net gave the Swiss a second wind.<br /><br />"It was an amazing match to win here," Wawrinka said. "Sam's a great player. To beat him in five sets is crazy.<br /><br />"I was just focused on my game, especially with the serve. I was not really happy with my serve. It didn't help me so much. I tried to adapt. With the wind, it was not easy."<br /><br />Wawrinka achieved the victory with a backhand volley past the frustrated American.<br />The 27th-ranked Wawrinka, who earned a top 10 spot in spring 2008, would bid to expand his success when he plays in the semi-finals against Russian 12th seed Mikhail Youzhny, a winner over Tommy Robredo 7-5, 6-2, 4-6, 6-4. <br /><br />"He is playing very strong from the baseline," Wawrinka said. "We've played a few times and had close matches."<br /><br />Holder Kim Clijsters won her 19th-straight match at the US Open Tuesday, setting up a semi-final with fellow two-time champion Venus Williams.<br /><br />The second seed claimed a break-strewn quarter-final over Australian Samantha Stosur, which featured more than 80 unforced errors between the pair before Clijsters came out the winner 6-4, 5-7, 6-3.<br /><br />Williams, who won the event in 2000 and 2001, put out Roland Garros champion Francesca Schiavone 7-6 (7-5), 6-4.<br /><br />Both matches were plagued by swirling wind, which made play a challenge. Clijsters managed the only holds in the final set in the first and last games. "Over the last 10 days, it's been tough to get used to the weather," the Belgian said. "Every match has been a battle. Mentally, you have to try and beat it."<br /><br />"Venus is a great competitor and is playing some great tennis," she added. "It will be a fun match. It's a challenge to be in another semi-final here."<br /></p>
<p>The world number one and top seed worked past midnight and into Wednesday for his victory, which set him up for a match against compatriot Fernando Verdasco.<br /><br />The eighth seed beat David Ferrer 5-7, 6-7 (8-10), 6-3, 3-6, 7-6 (7-4) on a day five Spaniards battled for advancement.<br /><br />Nadal and Verdasco are to play the first Spaniard-vs-Spaniard quarter-final at the Open. "Fernando is a complete player, one of the best," Nadal said after coming through with only two unforced errors in the third set. "He has all these shots and had an amazing comeback today."<br /><br />Swiss Stanislas Wawrinka dealt a blow to American tennis as he left the host nation without a men's quarter-finalist for the second year in a row after a 7-6 (11-9), 6-7 (5-7), 7-5, 4-6, 6-4 defeat of Sam Querrey.</p>.<p>Wawrinka, coached by Roger Federer's one-time mentor Peter Lundgren, reached the last eight of a Grand Slam for the first time in his career.<br /><br />It was a marathon lasting just over four and a half hours with plot twists galore. Querrey saved a match point in the final game as Wawrinka was unable to smash out of a lob, but an error into the net gave the Swiss a second wind.<br /><br />"It was an amazing match to win here," Wawrinka said. "Sam's a great player. To beat him in five sets is crazy.<br /><br />"I was just focused on my game, especially with the serve. I was not really happy with my serve. It didn't help me so much. I tried to adapt. With the wind, it was not easy."<br /><br />Wawrinka achieved the victory with a backhand volley past the frustrated American.<br />The 27th-ranked Wawrinka, who earned a top 10 spot in spring 2008, would bid to expand his success when he plays in the semi-finals against Russian 12th seed Mikhail Youzhny, a winner over Tommy Robredo 7-5, 6-2, 4-6, 6-4. <br /><br />"He is playing very strong from the baseline," Wawrinka said. "We've played a few times and had close matches."<br /><br />Holder Kim Clijsters won her 19th-straight match at the US Open Tuesday, setting up a semi-final with fellow two-time champion Venus Williams.<br /><br />The second seed claimed a break-strewn quarter-final over Australian Samantha Stosur, which featured more than 80 unforced errors between the pair before Clijsters came out the winner 6-4, 5-7, 6-3.<br /><br />Williams, who won the event in 2000 and 2001, put out Roland Garros champion Francesca Schiavone 7-6 (7-5), 6-4.<br /><br />Both matches were plagued by swirling wind, which made play a challenge. Clijsters managed the only holds in the final set in the first and last games. "Over the last 10 days, it's been tough to get used to the weather," the Belgian said. "Every match has been a battle. Mentally, you have to try and beat it."<br /><br />"Venus is a great competitor and is playing some great tennis," she added. "It will be a fun match. It's a challenge to be in another semi-final here."<br /></p>