NEW YORK, USA (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 yesterday.

Former world number one Ana Ivanovic, however, became the second top 10 seed to suffer a shock early New York exit as stiff winds brought new challenges at Flushing Meadows where players have already been tackling plus-30 degree heat (+90F) in the first week.

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 in course for a fifth successive final appearance.

Djokovic, whose last defeat at a major before the third round was at Wimbledon in 2008, looked more uncomfortable being asked to demonstrate some dance steps for the crowd than he did facing anything that Mathieu threw at him.

World number one Williams, chasing a third successive New York title, her sixth in total and an 18th major, fired 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.

Williams came into the US Open without a major this year but with five tour titles.

One of those came in Cincinnati where she defeated Ana Ivanovic whose Flushing Meadows campaign was ended by Karolina Pliskova of the Czech Republic.

Ivanovic, the eighth seed, lost 7-5, 6-4 to the 42nd-ranked Pliskova, who has reached the third round at a major for the first time.

The Serb followed fourth-seeded Agnieszka Radwanska out of the tournament after the Pole had been beaten by Peng Shuai 24 hours earlier.

Ivanovic came into New York as a potential title contender having captured trophies at Auckland, Monterrey and Birmingham this year while returning to the top 10 for the first time in five years.

But the former French Open champion was undone yesterday by 29 unforced errors while facing 13 break points as she crashed to her earliest exit in New York in six years.

There were no such dramas for third-seeded Petra Kvitova, who defeated Petra Cetkovska 6-4, 6-2.

The Wimbledon champion fired 23 winners past her 63rd-ranked fellow Czech and goes on to face either American 27th seed Madison Keys or Serb qualifier Aleksandra Krunic for a place in the last 16.

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.

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.