WIMBLEDON, England (AP) - Things got quite complicated for Rafael Nadal on Saturday.
His right knee was bothering him "a lot," something he later would say he's "a little bit scared about." His left elbow was briefly in pain, too, following one particular serve.
He got into a dispute with the chair umpire over whether Toni Nadal, Rafael's uncle, was coaching during the match, which is against the rules.
And then there was his most immediate concern Saturday: For the second consecutive round at Wimbledon, Nadal fell behind by two sets to one.
For the second consecutive round, though, the generally indefatigable Nadal came back and came through, this time pulling out a 6-4, 4-6, 6-7 (5), 6-2, 6-3 victory over 33rd-seeded Philipp Petzschner of Germany to reach the second week.
"This match was very difficult for me," Nadal acknowledged. "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."
That's when the grass-court Grand Slam tournament will resume after observing its traditional day of rest on the middle Sunday, all 32 players still in the event will be on the jam-packed schedule.
Nadal will meet 66th-ranked Paul-Henri Mathieu of France, who beat Thiemo de Bakker of the Netherlands 7-6 (5), 7-6 (6), 6-7 (8), 6-4. In his previous outing, de Bakker eliminated John Isner, the lanky American who won the longest match in tennis history, 70-68 in the fifth set.
No. 18 Sam Querrey of the United States won his own lengthy match, reaching Wimbledon's fourth round for the first time by defeating 2002 semifinalist Xavier Malisse of Belgium 6-7 (4), 6-4, 6-2, 5-7, 9-7. 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.
Next up for Querrey, 22, is a Centre Court contest against No. 4 Andy Murray, trying to become Britain's first Wimbledon men's champion since Fred Perry in 1936.
Murray, who hasn't dropped a set so far, beat No. 26 Gilles Simon of France 6-1, 6-4, 6-4 Saturday.
Other fourth-round men's matches Monday will include two-time French Open runner-up Robin Soderling of Sweden vs. No. 9 David Ferrer of Spain, and No. 10 Jo-Wilfried Tsonga vs. No. 32 Julien Benneteau in an all-French pairing.
Neither of those is nearly as intriguing as the women's matchup between 12-time Grand Slam champion Serena Williams and three-time major winner Maria Sharapova. It's a rematch of the 2004 Wimbledon final, which Sharapova won, but Williams leads their career series 5-2.
"I love going on the court and playing someone that's obviously the favorite," Sharapova said.
She struggled at the start of her 7-5, 6-3 victory over 68th-ranked Barbora Zahlavova Strycova of the Czech Republic. Defending champion Williams, in contrast, overwhelmed 46th-ranked Dominika Cibulkova of Slovakia at the outset of what would become a 6-0, 7-5 victory. Williams hit 19 aces and afterward declared: "For the most part my serve works when I'm in trouble. At Wimbledon it works the whole match."
Other women's fourth-round matchups include No. 3 Caroline Wozniacki of Denmark of vs. Czech Petra Kvitova; No. 7 Agnieszka Radwanska of Poland vs. No. 9 Li Na of China; and Estonian qualifier Kaia Kanepi vs. Klara Zakopalova of the Czech Republic.
None of the day's developments, however, was as significant as what happened while Nadal faced Petzschner, who lost in the first round at both of the year's first two major tournaments.
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.
At four separate changeovers, Nadal was visited by a trainer, who mostly worked on the player's right knee. 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 from 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."
Petzschner, playing his third five-setter in a row, sought help from a trainer for a recurring hip problem and faded late. He wondered aloud about how much medical help Nadal really needed Saturday, saying there didn't appear to be a difference in the No. 1-ranked man's movement before and after the trainer's visits.
"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 ... clever ... to take a timeout there."
Nadal denied there was gamesmanship involved.
"I never call the physio when I don't have (anything wrong) _ not one time in my career," he said. "If I (called) the physio today, it was because it was bothering me a lot, the knee."
Chair umpire Cedric Mourier warned Nadal during the fifth set about getting in-match coaching from his uncle, seated in the front row of the player guest box. Rafael Nadal pointed angrily at the umpire, spread his arms wide and shouted at him before returning to action.
Both Nadals said there was no coaching going on.
Instead, Toni Nadal explained, he was telling his nephew to stay positive.
"Nothing else," Toni Nadal said. If anything, the admonishment from Mourier appeared to spur on the younger Nadal, who reeled off the final three games of the match. After starting only 1 for 11 on break points, he went 3 for 3 down the stretch - and in sports, of course, all's well that ends well.
"Very difficult," Toni Nadal said, echoing his charge's phrase. "But at least Rafael won the match. So all is OK."