A bad back prevented Roger Federer from getting ready for the U.S. Open the way he prefers to prepare for a Grand Slam tournament. And it’s showed so far.

Federer blamed a lack of proper practice after making an uncharacteristic 68 unforced errors and being forced to go five sets again before coming back to edge a cramping Mikhail Youzhny 1-6, 7-6 (3), 6-4, 4-6, 6-2 on Thursday in Arthur Ashe Stadium.

It is the first time the 36-year-old Federer has played five-setters in both the first and second rounds at a major tournament.

“I knew I was going to maybe struggle early on. Maybe I struggled more than I would have liked to. But I’m still in the draw, which gives me a chance. I still believe I’m going to pick up my game and become just more consistent because I’m not playing all that bad,” Federer said. “It’s just that I’m going a bit up and down in waves throughout the match.”

Given that Federer entered the day with a 16-0 career record against Youzhny and a 16-0 mark in the U.S. Open’s second round, one might have thought that their match would be a mismatch.

Think again.

“He’s also a real man who plays tennis,” Youzhny noted. “He’s not a god.”

Well, OK, that’s true. But remember: Federer did not drop a single set en route to his record eighth Wimbledon championship in July. And that he is 37-3 with five titles, including two at majors to raise his record total to 19.

Heading in the right direction

The No. 3-seeded Federer won five consecutive U.S. Open championships from 2004-08 and also was the runner-up twice, including two years ago. But he missed last year’s tournament while taking off the second half of the season to let his back and surgically repaired left knee fully heal.

“I’m pretty confident that I’m only going to get better from here. That’s a good thing,” Federer said. “Because I’ve played a lot, I definitely found some rhythm now.”

Federer stumbled again while serving for the fourth set at 5-3, but responded to a break there by breaking right back.

At 1-all in the deciding set, Youzhny collapsed to the court, grabbing at his right leg after whiffing on an attempted swat at Federer’s lob. Youzhny stayed down for a few moments, then grimaced and limped around for the rest of that game.

Afterward, Youzhny chuckled at the mention of having lost all 17 matches against Federer, even leaning back in his chair and joking about how he would have completed the upset if Grand Slam rules were different: “I beat him in three sets now — but we played five sets. But come on, if we played three sets, I already beat him!”

Federer, naturally, preferred to look at matters from a different perspective.

“I find my way,” he said. “I don’t panic.”​

Federer will face Spain’s Feliciano Lopez in the round of 32. 

Nadal recovers from early struggles

Top-ranked Rafael Nadal came back from a set and a break down to beat Japan’s Taro Daniel 4-6, 6-3, 6-2, 6-2 and reach the U.S. Open’s third round.

It took Nadal a little while to figure out Daniel, who is ranked 120 spots lower and often plays on the lower-level Challenger tour. Daniel has never been past the second round at a major tournament.

Daniel was better in the opening set Thursday night and went ahead 2-1 in the second. But Nadal finally converted a break point on his sixth try of the match in the next game to get to 2-all and began to calibrate his big forehand better.

Match Wrap: Rafael Nadal advances to third round at US Open1:38

Nadal has won his past 11 second-round matches at Flushing Meadows after losing in first two appearances at that stage back in 2003 and 2004.

Nadal is a 15-time Grand Slam champion, including titles at the U.S. Open in 2010 and 2013.

He plays 59th-ranked Leonardo Mayer next.

Top seed Pliskova rallies to move on

No. 1 Karolina Pliskova has advanced to the third round by rallying for a 2-6, 6-3, 6-4 victory over American Nicole Gibbs.

Pliskova turned around the match after a slow start to avoid becoming the fifth player among the top seven seeds to be eliminated.

The Czech has plenty more to do if she wants to keep the No. 1 ranking. She has to reach the final, or win the title if Garbine Muguruza loses in the semifinals.

Top seed Karolina Pliskova avoids a major upset at the US Open1:01

Rogers wins record marathon match

American Shelby Rogers beat Daria Gavrilova 7-6 (6), 4-6, 7-6 (5) in 3 hours, 33 minutes, setting the record for the longest women’s match in U.S. Open history.

After Gavrilova’s backhand sailed long on match point, the 62nd-ranked Rogers raised her arms and then put her hands to her face and broke into tears. She said after the match that it didn’t feel like the longest ever at Flushing Meadows but that now she knows that, “I’m going to be sore.”

Previously, the longest women’s match at the tournament was in the 2015 second round when Johanna Konta downed Garbine Muguruza 7-6 (4), 6-7 (4), 6-2 in 3:23.

Dimitrov latest men’s seed to bow out

No. 7 seed Grigor Dimitrov became the latest top-10 man to bow out of the U.S. Open, upset in the second round by 19-year-old Russian Andrey Rublev.

The 53rd-ranked Rublev eliminated Dimitrov 7-5, 7-6 (3), 6-3 to reach the third round at a major tournament for the first time.

Dimitrov is a three-time Grand Slam semifinalist who had been playing well leading into Flushing Meadows. He had won 13 consecutive sets heading into Thursday, dating to the Cincinnati Masters, where he won his first title at the tour tier just below the majors.

Against Rublev, Dimitrov double-faulted 11 times and converted only 2 of 10 break points.

Dimitrov’s exit raises to six the number of members of the ATP’s top 10 who are out of the field in New York already. No. 2 Andy Murray, No. 4 Stan Wawrinka, No. 5 Novak Djokovic and No. 10 Kei Nishikori all sat out the U.S. Open with injuries, and No. 8 Jo-Wilfried Tsonga lost to 18-year-old Canadian Denis Shapovalov in the second round Wednesday night.