|Wozniacki returns against Yung-Jan Chan as the Danish top seed lost just one game of a straight-sets win [AFP]
Top seed Caroline Wozniacki and former world number one Maria Sharapova booked a fourth-round showdown with straight-set US Open triumphs while Roger Federer cruised into the last 16 of the men's competition.
Danish 20-year-old Wozniacki, last year's US Open runner-up, routed Taiwan's Chan Yung-Jan 6-1, 6-0, while Russian 14th seed Sharapova, whose three grand slam titles include the 2006 US Open, blanked American Beatrice Capra 6-0, 6-0.
Wozniacki has lost only three games in three matches, the best US Open run since Chris Evert dropped only two in the same span in 1976.
"She can run all day and get a lot of balls back and make you hit tons of balls," Sharapova said.
"She changes pace really well and gets her opponents off balance. She does many things well. That's why she's at the top.
"It will be tough and I am looking forward to it."
Sharapova, whose blanking of Capra was the latest US Open women's shutout since Martina Navratilova won by the same score in 1989, beat Wozniacki twice in 2008 in their only prior meetings.
Since then Wozniacki has risen through the ranks to become world number two behind Serena Williams, going 17-1 with three titles since Wimbledon.
"She is a good player, a tough match-up," Wozniacki said. "We will see what happens on Monday."
A showdown is brewing on the men's side as well as Federer, a 16-time grand slam champion seeking his sixth US Open title and seventh consecutive trip to the final, and Swedish fifth seed Robin Soderling reached the fourth round.
World number two Federer smashed 13 aces and 31 winners to beat 109th-ranked Frenchman Paul-Henri Mathieu 6-4, 6-3, 6-3 while Soderling defeated 48th-ranked Dutchman Thiemo de Bakker 6-2, 6-3, 6-3.
Both triumphs came in brisk winds.
"Tough conditions to play in, especially if you're down in the score," said Federer.
"You could tell Mathieu was really struggling after being down. His serve, his returns, everything kind of falls into pieces."
French Open runner-up Soderling broke Federer's streak of 23 grand slam semi-finals in a row with a quarter-final triumph on the Paris red clay over the Swiss superstar who had won their 12 prior matches.
Soderling, who lost the Roland Garros final to top-ranked Rafael Nadal, and world number two Federer each need one more victory to book a rematch on the Flushing Meadows hardcourts.
"Everybody has been telling me since the draw came out I'm playing Roger in the quarters. It's still far ahead," Soderling said.
"It's always difficult to play against Roger and I have played him a lot of times. In any tournament they play, Roger and Rafa will be the favourites, but there are a lot of players who can beat them."
Federer next faces Austrian 13th seed Jurgen Melzer, whom Federer ousted in this year's fourth round at Wimbledon in their only prior meeting.
Soderling will meet Spanish 21st seed Albert Montanes, who led 6-2, 2-1 when 147th-ranked Japanese qualifier Kei Nishikori retired after only 38 minutes with a groin injury.
Also advancing to the fourth round was Serbian third seed Djokovic, who downed US wildcard James Blake 6-1, 7-6 (7/4), 6-3 to book a date with US 19th seed Mardy Fish.
The day's biggest upset came on the women's side when Serbian fourth seed Jelena Jankovic, a former world number one who was a 2008 US Open runner-up, was wind-hampered and lost 6-2, 7-6 (7/1) to Estonian 31st seed Kaia Kanepi.
"It was really difficult," Jankovic said. "I didn't have a chance to play good tennis in these conditions."
Kanepi will next play Belgian Yanina Wickmayer, a 2009 US Open semi-finalist who saved a match point in the final tie-breaker before beating Swiss veteran Patty Schnyder 7-6 (7/5), 3-6, 7-6 (8/6).