he Associated Press, Madrid | Fri, 05/14/2010 7:14  AM | Sports     
  
No sweat: Roger   Federer from Switzerland returns the ball during the match against  Stanislas Wawrinka from Switzerland at the Madrid Open Tennis Tournament  in Madrid, on Thursday. AP/Andres Kudacki
Roger   Federer and Rafael Nadal comfortably reached the quarterfinals of the  Madrid Masters on Thursday.
The top-ranked Federer beat Swiss  countryman Stanislas Wawrinka 6-3, 6-1 and second-ranked Nadal saw off  big-serving John Isner of the United States 7-5, 6-4.
Defending  champion Federer never looked troubled against Wawrinka, and appears to  be shaking off the dip in form that saw him lose in the semifinals in  Estoril and the second round in Rome recently. In the quarterfinals  he'll play Ernests Gulbis of Latvia, who beat him in Rome.
Isner,  who reached the clay final in Belgrade last weekend, held his own  against Nadal before losing his serve in the 11th game of the first set,  during which he received treatment to his arm.
Nadal served out  for the set and broke the American early in the second before holding  his service for victory.
"It was a very dangerous and difficult  match and I played well, and when I had chances with the return I took  them," said Nadal. "For me it was a very important victory."
Nadal   came into the Madrid Masters on the back of tournament wins in Monte  Carlo and Rome. The 2005 champion and 2009 finalist hopes to extend the  record for Masters titles of 17 he shares with Andre Agassi.
Another   favorite to win the tournament, third-seeded Andy Murray, had little  trouble beating Victor Hanescu of Romania 6-2, 6-1.
Two breaks of  serve in each set saw the Scot stroll to victory, setting up a  quarterfinal with David Ferrer, who beat Marin Cilic of Croatia 6-3,  6-2.
Murray hadn't won two matches in a row since Indian Wells in  March and he was pleased.
"Hanescu isn't an out-and-out  clay-court player so it was a different match than you normally get, but  I felt comfortable," Murray said.
"I know that against the  clay-courters I'll have to play more aggressively and will have to  improve."
Earlier, Fernando Verdasco's 7-5, 6-3 third-round loss  to Jurgen Melzer of Austria left only three of the top eight seeds in  the tournament.
With the center court's retractable roof closed  due to rain, the sixth-seeded Verdasco looked well below his best and  had treatment on his right ankle after the first set.
Melzer  broke early in the second set before Verdasco broke back for 3-3. Melzer  took the next three games to clinch victory over Verdasco for the  second time in seven attempts and reach his fifth quarterfinal this  season.
A frustrated Verdasco said his ankle was hurting after he  injured it in the previous round against Ivo Karlovic, although he said  the match conditions also bothered him.
"I haven't played  indoors for months and I've never had the opportunity to train here with  the roof closed - I think it gave him the advantage," he said. "He's  more of an indoor player than an outdoor player, which also went against  me. The court also wasn't in the best condition, which made me miss  certain shots that were very important."
Melzer will next play  Nicolas Almagro of Spain, ensuring there will be at least one unseeded  player in the semifinals. Almagro beat Juan Monaco of Argentina 6-4,  6-1.
In the women's third round, eighth-seeded Samantha Stosur of  Australia beat Patty Schnyder of Switzerland 7-6 (3), 6-2 to set up a  quarterfinal with Venus Williams.
"It's Venus so you have to  expect a good match," Stosur said. "Clay probably isn't her favorite  surface. We've played a few times and I've never been able to win so  it's one of those times when I have to go out there and give it my best  shot."
Seventh-seeded Jelena Jankovic of Serbia cruised through  against Anabel Medina Garrigues of Spain, 6-2, 6-0, while Aravane Rezai  of France beat Andrea Petkovic of Germany, 6-4, 7-6 (8).
Li Na of  China beat Alona Bondarenko of Ukraine 6-3, 6-4 and Shahar Peer of  Israel defeated Arantxa Parra Santonja of Spain 7-5, 6-2.