Clijsters makes short work of dispatching old friend Ivanovic

When Ana Ivanovic was struggling not so long ago Kim Clijsters would send her text messages of support but, in Arthur Ashe Stadium yesterday, there was never any chance of the defending US Open champion showing the Serb any mercy. Clijsters, striking the ball with her customary power, won 6-2, 6-1 in just 59 minutes to earn a quarter-final meeting with either Samantha Stosur or Elena Dementieva, who were due to play the day's final match on the main show court.

While Ivanovic has made good progress in recent months – she was down to No 65 in the world rankings two months ago but is back at No 40 and will climb again in next week's updated list – this was a sharp reminder of the work she still has to do. The former world No 1, who had not dropped a set in her first three matches, had her serve broken six times as Clijsters showed the kind of form that took her to the title here 12 months ago.

Ivanovic pulled back an early break to trail 3-2 in the first set, but thereafter she was overpowered, losing seven games in a row. Clijsters' big groundstrokes regularly had the 2008 French Open champion on the back foot and she made 28 unforced errors.

Clijsters has failed to go beyond the quarter-finals in her last two Grand Slam tournaments, but the north American hard-court season brings the best out of the Belgian, who won her only other Grand Slam title here in 2005. She won in Cincinnati last month and has lost just 14 games in four matches here.

The wind, a legacy of Hurricane Earl, had calmed down a little from the previous day, but the conditions were still tricky. "At the beginning you have to settle down with the wind and adjust, especially with the serve," Clijsters said afterwards.

Francesca Schiavone was another player in a hurry. The Italian reached the quarter-finals for the second time with a 6-3, 6-0 victory over Russia's Anastasia Pavlyu-chenkova. Schiavone could barely win a match in the wake of her triumph at the French Open in June but has rediscovered her form here, reaching the last eight without losing a set. "I feel better than when I was at the French Open, because I know how to win a match like this," she said.

In the quarter-finals, Schiavone will play Venus Williams, who was pushed early by Israel's Shahar Peer before winning 7-6, 6-3.