CINCINNATI: Rafael Nadal is taking his demotion to world number three in his stride and focusing on the long-term as he continues his comeback from injury at the Cincinnati Masters this week.

"It's only a number," Nadal said Monday. "I hope to be ready in the future to come back to No. 2 or to be in the top position.

"No. 3 is a very good number, too," he added with a smile.

The 23-year-old Spaniard, forced out of Wimbledon by his aching knees, returned last week in Montreal after an absence of more than two months.

His run to the Canadian quarter-finals wasn't enough to stop eventual champion Andy Murray from seizing the world number two spot behind Switzerland's Roger Federer.

Nadal said he wouldn't let the rankings - or anything else - lure him into pressing too hard, too soon, as he battles to come back and finish the season on a high note.

"I need to go slow, no?" Nadal said, even if that means he won't be at his best for the US Open that starts in a fortnight.

"Sure, the US Open is very important," Nadal said. "But after the US Open remains a lot of the season, and I would like to be ready to play a good end of the season."

For this week, at least, Nadal still has the number two seed behind Federer, with defending champion Murray seeded third in the same half of the draw as Federer.

The top eight all enjoy first-round byes, and ninth-seeded Frenchman Gilles Simon was the highest seed in action, posting a 6-3, 6-2 victory over American Wayne Odesnik.

Simon was one of a trio of Frenchmen to advance. Jeremy Chardy upset 15th-seeded Spaniard Tommy Robredo 6-3, 7-5 and Paul-Henri Mathieu defeated Germany's Mischa Zverev 6-7 (4/7), 7-5, 6-3.

Two other Frenchmen were less fortunate, Florent Serra falling to Croatian veteran Ivan Ljubic and Gael Monfils falling to Ljubic's countryman Ivo Karlovic .

Croatia's Marin Cilic also advanced, downing former world number one Juan Carlos Ferrero of Spain 6-3, 6-4

Argentina's Jose Acasuso earned a second-round match against Federer with a 6-4, 6-3 victory over Polish qualifier Lukasz Kubot.

Spain's Nicolas Almagro booked a clash with Murray. Almagro was up 6-4, 1-0 against Dudi Sela when the Israeli retired.

Murray, who beat Serbia's Novak Djokovic in last year's final here, beat Argentina's Juan Martin Del Potro in the final at the Montreal Masters on Sunday.

Del Potro, who won the title in Washington the week before Montreal, was the sixth seed here but withdrew on Monday citing fatigue.

Federer, who claimed his record 15th Grand Slam title with a five-set victory over Andy Roddick in the Wimbledon final, has taken time away since as he and wife, Mirka, welcomed the arrival of twin daughters last month.

He, too, lost in the quarters in Montreal.

Federer said it was good to have Nadal back in the frame in time for the final Grand Slam of the year at Flushing Meadows later this month.

"Andy (Murray) and myself have both benefited from Rafa being injured," Federer said. "We both took advantage of it.

"Now, he's back, I'm back playing again after a few weeks. Everybody seems healthy again, and that can only be a good thing for the rest of the season."