Gael Monfils says he plans to skip Wimbledon for personal reasons, making the announcement after defeating a qualifier at the Gerry Weber Open in Halle, Germany on Wednesday.

Monfils says he withdrew his request for a wild card at Wimbledon because he had to deal with a personal problem. The Frenchman gave no details.

Earlier Wednesday, Monfils reached the quarter-finals of the tournament by defeating qualifier Jan Hernych 6-2, 6-3.

Once ranked No. 7, Monfils missed several months last year because of a knee injury. He was ranked No. 119 in May before improving to No. 67 this week after reaching the third round of the French Open.

He beat Canadian Milos Raonic on Tuesday and got past top player Tomas Berdych in the second round of the French.

That said, Wimbledon has traditionally been the least successful of the majors for the 26-year-old Monfils. He's never made it past the third round.

For a player who says he has trouble moving on grass, Monfils was at his acrobatic best against Hernych.

At one point, he even jumped over the net. Trying to save a break point, the Czech qualifier dived to his right to reach a ball at the net and managed to send it over. Monfils raced forward, failed to reach it in time and his momentum carried him over the net. The two touched hands and Monfils got back to his side to eventually break serve for a decisive 4-2 lead in the second set.

The Frenchman's enthusiasm did not always result in points — he once jumped high for a smash, only to rip it into the net. But another time, he chased down a lob and hit a perfect backhand winner on the turn.

"I was happy, I was having fun," Monfils said. "Grass is not natural for me, but I am getting better. I have to focus on not falling, not injuring myself. I cannot take off as fast as I want to and I have problems braking. But I was comfortable today, I was leading all the time."

Top-seeded Roger Federer looked rusty but beat German wild card Cedrik-Marcel Stebe 6-3, 6-3 Wednesday to reach the quarters of the event.

Mikhail Youzhny also advanced to the last eight by upsetting fourth-seeded Kei Nishikori 6-1, 6-7 (4), 6-3. German wild card Mischa Zverev went through by beating Mirza Basic 7-6 (5), 6-3 after coming from behind in both sets.

Four of Federer's seven Wimbledon titles have come after Federer had also won the tune-up event in Halle. His link to the Halle event is so deep that he has had a street named after him.

Now ranked No. 3 in the world, Federer has not won a title this year and is coming off a quarter-final loss to Jo-Wilfried Tsonga at the French Open.

Serving for the first set, Federer produced four straight errors to waste two set points and drop his serve with some very sloppy play. He bounced back in the next, however, to win the set.

Federer hit two wild backhands to help Stebe hold his serve in the seventh game of the second. Federer also committed a double-fault on his first match point, but hit a volley winner to end it.

Youzhny was not quite as spectacular as Monfils but his steady game carried him past Nishikori in the first set.

"He started well, he was hitting a lot of first serves and I was missing everything," the Japanese said.

Nishikori said it was not easy to adjust to grass and that he would remain in Halle for a while to practice more and play doubles.

Basic, a Bosnian who upset seventh-seeded Jerzy Janowitz in his first match in the main draw of an ATP Tour event on Tuesday, squandered a 4-1 lead in the first set and a 2-1 break lead in the second. He saved three match points on his serve but Zverev closed it out with a service winner.

Cilic, Berdych advance at Queen's

Defending champion Marin Cilic advanced to the third round at Queen's Club with a 6-3, 6-4 win over fellow Croat Ivan Dodig on Wednesday.

The No. 5-seeded Cilic was never under pressure and Dodig failed to earn a break point.

Cilic won the title last year when David Nalbandian was defaulted for violent conduct after he kicked an advertising sign and injured a line judge.

Berdych held off a strong second-set challenge from Dutchman Thiemo De Bakker to win 6-1, 6-4.

It was the Czech's first appearance at the pre-Wimbledon grass event since he was defeated in the first round in 2005.

The No. 2-seeded Berdych dominated the opening set and won 70 per cent of the points, but after a short rain delay at the start of the second set De Bakker held six break points before Berdych earned a vital break to lead 4-3.

Four-time champion Lleyton Hewitt also reached the third round with a 6-4, 6-3 upset victory over Grigor Dimitrov of Bulgaria.

With files from