New York (AFP) - Novak Djokovic reached the third round of a Grand Slam for the 25th consecutive time while Serena Williams racked up her 80th US Open win as the top seeds eased into the third round on Thursday.
But former world number one Ana Ivanovic, the eighth seed, and 2011 champion Samantha Stosur were knocked out on a day when stiff winds brought new challenges at Flushing Meadows for players already tackling plus-30 degree heat (+90F).
World number one and top seed Djokovic breezed past France's Paul-Henri Mathieu 6-1, 6-3, 6-0, firing 13 aces and 33 winners as the 2011 champion comfortably remained on course for a fifth successive final appearance.
"It's very windy, but I managed to adjust to the conditions that obviously are not easy for myself and my opponent," said Djokovic, who next meets Sam Querrey of the United States, after his brief 90-minute appearance.
World number one Williams, chasing a third successive New York title, her sixth in total and an 18th major, sent 25 winners past Vania King and broke serve six times, wrapping up a 6-1, 6-0 victory on windswept Arthur Ashe Stadium in just 56 minutes.
It was her second win over an American at the tournament this week after beating teenager Taylor Townsend and next she will face another in Varvara Lepchenko for a place in the last 16.
"It's so hard to play in the wind but I am happy to get through a solid match with the conditions today," said the top seed whose colourful leopard print dress was as striking as her tennis.
Eighth-seeded Murray brushed aside 27-year-old German qualifier Matthias Bachinger, the world number 235, with a convincing 6-3, 6-3, 6-4 win.
Murray exhibited none of the physical problems he suffered in the first round when he was cramping, sending down 36 winners past Bachinger, a contemporary from his junior days.
"Both of us struggled a bit early on but once I started to get used to the wind I was able to adjust my tactics a bit," said the Scot.
Canadian fifth seed Milos Raonic made the third round with a 7-6 (7/4), 5-7, 6-4, 7-6 (7/3) win over German qualifier Peter Gojowczyk on the back of 26 aces and 64 winners.
- Ivanovic, Stosur beaten -
Eighth-seeded Ana Ivanovic suffered her earliest US Open exit in five years when the former world number one lost 7-5, 6-4 to Karolina Pliskova of the Czech Republic, the world number 42.
The Serb followed fourth-seeded Agnieszka Radwanska out of the tournament after the Pole had been beaten by Peng Shuai 24 hours earlier.
The former French Open champion was undone by 29 unforced errors.
"It's very disappointing. It's never easy to finish this early," said Ivanovic. "I'm definitely going to assess what went wrong and what I can work on. I really felt it wasn't my game out there today."
Stosur, the 24th seed, squandered two match points in a 3-6, 6-3, 7-6 (10/8) defeat to Estonia's Kaia Kanepi, a six-time Grand Slam quarter-finalist.
There were no such dramas for Kvitova who defeated fellow Czech Petra Cetkovska 6-4, 6-2 while Canadian seventh seed Eugenie Bouchard, the runner-up at Wimbledon, beat Sorana Cirstea of Romania 6-2, 6-7 (4/7), 6-4.
Victoria Azarenka, the runner-up to Williams for the past two years, also made it through, winning nine games in succession from 0-3 down to defeat Christina McHale of the United States 6-3, 6-2.
Fifteen-year-old American CiCi Bellis, who became the youngest winner of a US Open match since 1996 when she won her first round match, went down 6-3, 0-6, 6-2 to Zarina Dyas of Kazakhstan.
The United States only saw three men making the second round -- the country's lowest total in the history of the tournament -- but 13th seed John Isner and Querrey have made it to the last 32.
Isner, a quarter-finalist in 2011, beat Germany's Jan-Lennard Struff 7-6 (7/5), 6-4, 6-2 while Querrey beat Spain's Guillermo Garcia Lopez for the fourth time in four meetings -- including last week's Winston Salem warm-up -- thanks to a 6-3, 6-4, 6-4 victory.
Australian 19-year-old Nick Kyrgios, who famously defeated Rafael Nadal at Wimbledon, reached the third round by seeing off Italy's Andreas Seppi 6-4, 7-6 (7/2), 6-4.
He will next face Spanish veteran Tommy Robredo who came back from two sets to love down for the seventh time in seeing off Italy's Simone Bolelli 5-7, 6-7 (5/7), 6-4, 6-3, 6-2.