In her first match since winning Wimbledon, the top seed shrugged off a slow start to set up a clash with former world number one Lindsay Davenport, who beat Italian Francesca Schiavone 6-4, 6-2.

Frenchwoman Mauresmo was lethargic in the early stages and Voskoboeva, the world number 93, took advantage in the first set.

Any thoughts of an upset were soon dashed though as Mauresmo cruised through the next two sets.

"I was not surprised it took me some time to get into the rhythm," said Mauresmo, whose return to the Tour had been delayed by a week due to a shoulder injury.

"I think it's a little normal. There were a few good things and a few things still need working on but hopefully they will get there by next week (before the U.S. Open)."

Davenport set up a repeat of last year's New Haven final with a confident victory over Schiavone.

The American, in just her second tournament back after five months out with a back problem, eased through in 68 minutes.

Davenport has won 11 of her 14 meetings with Mauresmo, including the past 10, but the American said their quarter-final would be a different match altogether.

"It will be interesting to play her a year later to see the improvement she has made," Davenport said.

"She's kind of a different player with a couple of grand slams under her belt. It should just be fun to see how both of us are right now."

Third seed Elena Dementieva survived a second-set wobble to defeat Slovakia's Daniela Hantuchova 6-2, 5-7, 6-0.

The Russian, who won the title in Los Angeles earlier this month, now plays compatriot Svetlana Kuznetsova in a repeat of the 2004 U.S. Open final, which Kuznetsova won.

Fourth seed Nadia Petrova was upset 4-6, 6-4, 7-6 by Marion Bartoli of France.

Later on Wednesday, Belgian second seed Justine Henin-Hardenne opens her title campaign against Spaniard Anabel Medina Garrigues.

In the men's event, second seed Nikolay Davydenko took his place in the last eight thanks to a 6-4, 6-1 win over Paradorn Srichaphan of Thailand.

But fifth seed David Ferrer of Spain was beaten 6-3, 6-1 by number 10 Agustin Calleri of Argentina.

Belgian Olivier Rochus ousted Frenchman Gael Monfils 6-4, 6-3 while Juan Ignacio Chela beat fellow Argentine Jose Acasuso 7-6, 6-2.

Lucky loser Jurgen Melzer advanced to the last eight when Spaniard Fernando Verdasco retired injured with the Austrian leading 6-4, 4-1.