WIMBLEDON, England -- Second-seeded Rafael Nadal rallied for another five-set victory to reach the fourth round at Wimbledon, overcoming physical ailments and a warning for coaching.
The Spaniard battled back from two-sets-to-one down to defeat Germany's Philipp Petzschner 6-4, 4-6, 6-7 (5), 6-2, 6-3 in a 3½-hour Centre Court slugfest Saturday.
Nadal, who won the title in 2008 but missed last year's tournament due to knee troubles, called for the trainer four separate times for treatment on his left arm and right leg.
"I hope I'll be fine," Nadal said. "I don't know. I'm going to check. It's not a big problem. It's a long season for me. I have played a lot of matches the last few months.
"Having a five-set match two days ago and one today -- that's tough. I'm happy to be in the fourth round. I'm going to try to be better for Monday."
Nadal said he will definitely play Monday's match against France's Paul-Henri Mathieu, who beat Thiemo de Bakker in four sets.
"I am here to try my best and to try to keep in the tournament," he said.
Nadal has won seven Grand Slam titles, including at the French Open this month, and never before has he won two five-setters en route to a major's fourth round. But the Spaniard went the distance against 151st-ranked Robin Haase of the Netherlands on Thursday, then did so again Saturday.
Tendinitis in both knees forced Nadal to pull out of Wimbledon a year ago instead of defending his 2008 title, and he disclosed for the first time Saturday that he's been dealing with knee issues this season.
Nadal said he received "new treatment" that helped his left knee after winning a clay-court title at Monte Carlo in April, but did not have time to get the same work done on the right side. Asked to describe the treatment, he said, "I can't explain [it] now, especially in English. Sorry."
He'll skip Spain's Davis Cup quarterfinal against France on July 9-11 so the same procedure can be carried out on his right knee, because he wants to be healthy in August for the U.S. Open, the only major title missing from his resume.
As for how the knee might effect him at Wimbledon, Nadal said: "I hope I'll be fine. I don't know. I'm going to check."
The left-hander was worried momentarily when he felt something in that elbow, but said that went away quickly and declared, "The arm is perfect."
Fourth-seeded Andy Murray followed Nadal on Centre Court and beat Frenchman Gilles Simon 6-1, 6-4, 6-4, keeping alive Britain's hopes for a first homegrown male champion since 1936.
Murray, who hasn't dropped a set so far, served 15 aces, conceded only 15 points on serve and did not face a single break point.
On Monday, Murray will play American Sam Querrey, who defeated unseeded Belgian Xavier Malisse in five sets, for a berth in the quarterfinals.
"I think it'll be 99 percent for Murray," Querrey said, "and, like, my mom and dad and sister cheering for me."
The 18th-seeded Querrey won 6-7 (4), 6-4, 6-2, 5-7, 9-7 to reach the round of 16 at the All England Club for the first time.
Querrey, 22, served for the match at 5-4 in the fifth set only to be broken, but converted the second time after breaking Malisse in the 15th game of the set. The final point was played at 9:23 p.m., and Querrey figured the match would have been suspended and continued Monday if he hadn't won when he did.
The 33rd-seeded Petzschner, playing his third straight five-setter, also needed medical treatment for a recurring hip problem on several changeovers and looked exhausted in the final set.
The German questioned Nadal's injury breaks.
"You have to ask him what it was. But I didn't feel any difference afterwards or before. I thought he was moving great. I only could say if I would be injured like this once I would be happy. I don't know. Maybe he had something. Maybe it was just a clever part to take a time-out there."
Nadal denied any gamesmanship.
"I never call the physio when I don't have nothing, not one time in my career," he said. "If I call the physio today, it was because it was bothering me a lot, the knee."
Nadal received a warning from chair umpire Cedric Mourier at 2-2 in the fifth set for receiving coaching from coach and uncle Toni Nadal, who was sitting in the front row of the players' guest box. Rafal Nadal pointed angrily at the umpire, spread his arms wide and shouted at him before resuming play.
Nadal said he told the umpire he wants to discuss the issue later with the tournament supervisor.
"He wasn't giving me any tip," Nadal said. "He was only supporting me."
Toni Nadal denied coaching, saying he was only encouraging the player.
"I say, `Positive! Positivo!' Nothing else," he said.
The incident seemed to inspire Nadal, who closed out the game with an overhead and looked over at his uncle with a sneer as he walked to his chair.
After a service hold by the German, Nadal ran off the last three games to finish the match. He got the decisive break to go up 5-2 when Petzschner missed a tired forehand wide. Nadal served out the match at love, then pumped his arms and saluted the crowd as he basked in a big ovation.
Nadal looked on the ropes for a while against the 26-year-old German. Petzschner served 25 aces and finished with 63 winners, compared to 56 for Nadal. But he also had 40 unforced errors, compared to 18 for the Spaniard.
Nadal faced only two break points and was broken just once, but went 1-11 on break points until converting his last three.
Sixth-seeded Robin Soderling, a two-time French Open finalist, beat the 24th-ranked Thomaz Bellucci 6-4, 6-2, 7-5 in a little less than two hours.
After breezing through the first two sets, the Swede faced a stiffer challenge from the left-handed Brazilian in the third, when he saved three break points in the penultimate game of the match.
Soderling is one of only three men yet to drop a set at Wimbledon, where he has reached the round of 16 for the second consecutive year.
Men's winners included ninth-seeded David Ferrer, who will next play Soderling, and Frenchmen Jo-Wilfried Tsonga and Julien Benneteau.
The Associated Press contributed to this story.