CINCINNATI: World number one Roger Federer had to work for his quarter-final berth at the Cincinnati Masters on Thursday, while newly-minted number two Andy Murray cruised through with relative ease.

Swiss top seed Federer rallied for a 3-6, 6-3, 6-4 victory over Spain's David Ferrer, conquering not only the world number 19 but also the difficult, windy conditions to line up a meeting with Aussie Lleyton Hewitt.

Hewitt overcame American Sam Querrey 6-1, 2-6, 6-3 to earn a shot at the Swiss superstar.

"It is a fantastic challenge to play him and play the best players in the world especially after hip surgery last year," Hewitt said.

Murray, meanwhile, needed just 1hr 16min min to beat Czech Radek Stepanek 6-4, 6-1.

Federer stretched his career lead over Ferrer to 9-0, but for a while it looked like the Spaniard might notch that first win against his mighty opponent.

He broke Federer for a 5-3 lead, then held at love to pocket the first set.

Federer went down an early break in the third, but this time he immediately broke back and cruised home from there.

"You have a certain attitude out there and certain approach," Federer said of the need to stay calm and focused in tight situations.

"Mine was that I tried to stay calm and not give too much away to my opponent and try to hang in there and even when it's tough sometimes, accept it and try to turn it around.

"Today I didn't think I was going to because I thought David was playing a great match," Federer admitted. "That's why the satisfaction is maybe greater now."

Federer said he struggled in the early going with his footwork - a key in the windy, unpredictable conditions.

"I think I got it together and started to play better and better," he said. "In the end when it goes your way, all of a sudden you can actually use the wind to your advantage in a big way."

Federer, who lost in the quarter-finals of the Montreal Masters last week, was delighted to be looking forward to another match.

After notching his first career French Open crown and then taking his Grand Slam tally to a record 15 at Wimbledon, Federer took some time off as he and his wife, Mirka, welcomed the birth of twin daughters.

"For me it's just really getting match play," he said of what he needs as the US Open approaches.

"I'd like to play sometimes a bit more aggressive or a bit more with spin ... those little ideas you have sometimes that need to come at the right time.

"For that you need matches. That's why this win today was perfect. Gives me another opportunity to play another match."

In the quarter-finals Murray will face France's Julien Benneteau, a 4-6, 6-4, 7-6 (7/4) winner over Spain's Guillermo Garcia-Lopez.

Murray said the windy weather wrong-footed him a few times. But apart from one service break in the opening set he was able to cope.

"I played a good game to break back," the Scot said. "Had a couple of good returns, and obviously a lob to finish with was nice. After that, started to feel a lot better."

Murray said he knew before he took the court tha patience would be crucial.

"I saw a little bit of Federer's match before I was going on," he said. "You know, you can't play to the lines. You're going to mis-hit some shots. It's just important to not get too frustrated."

Fourth-seeded Serbian Novak Djokovic also advanced, defeating France's Jeremy Chardy 7-5, 6-3.