By Martyn Herman

LONDON (Reuters) - Rafa Nadal suffered a late blip against unseeded Czech Radek Stepanek before reaching the quarter-finals of the Queen's Club championships Thursday after Andy Murray and Andy Roddick both cruised through.

"For sure, I'm a bit tired," Nadal said on court before hurrying off to play doubles with partner Marc Lopez.

"5-2, 5-3, 40-15 he played well. I had a few mistakes and you know that's the turning point. The beginning of the third was tough but after that I think I played my best. Much better than yesterday."

Second seed Murray, who will spend the next few weeks shouldering Britain's hopes of a first men's grand slam champion since 1936, beat flashy Serb Janko Tipsarevic 6-4 7-6 despite losing his service at the start of each set.

Another Argentine to fall was Juan Martin del Potro who was bundled out in two tiebreaks by Frenchman Adrian Mannarino.

Croatia's Marin Cilic made it a bad day for south Americans as he ousted Brazil's Thomaz Bellucci 7-6 0-6 6-3 to seal a last-eight clash against Murray.

Nadal is usually ruthless when an opponent is on the ropes, but serving at 5-3 in the second set he wasted two match points and then threw in a double fault to give Stepanek a lifeline.

Then, at 5-5, he played another messy game and suddenly the mercurial Czech veteran was serving for the second set, which he did in some style, leveling the match with a lunging volley.

While the crowd, some of them perched on the balconies of the rambling Victorian clubhouse, loved it, Nadal was clearly not amused and stormed through the deciding set in quick time to set up a last eight meeting with fifth seed Jo-Wilfried Tsonga.


The Scot appears to like setting himself puzzles to solve though and the way he recovered both times with some dazzling shot-making and thumping serves left him feeling upbeat.

Even better news was his suspect right ankle, injured at the French Open, showed signs of improvement.

"If I had gotten off to better starts I could have won more easily but I was always trying to get myself back into it. I did a good job of that."

After an impressive victory against dangerous Feliciano Lopez in the previous round, the third seed said he was happy with his form at his favorite time of the year.

"Everything felt fine," Roddick, three-times a Wimbledon runner-up to Roger Federer, told reporters.

"He had some chances to break. He didn't get them. I had a couple chances and I converted. That was pretty much the story of the match," added Roddick, who fired down two 225kph bullets toward the end of the match, proof that his famed serving shoulder is in fine fettle.

Two French players were forced to withdraw injured. Gilles Simon retired with a back strain at 3-0 down in the third set against compatriot Mannarino in a second round match held up overnight and Michael Llodra quit with a thigh injury in the first set against Tsonga.

(Reporting by Martyn Herman; editing Pritha Sarkar)