Swiss mogul Roger Federer needed a second successive five-setter to reach the US Open third round on Thursday while Rafael Nadal of Spain also made it to third round.
The match, a 6-1, 6-7(3), 4-6, 6-4, 6-2 win over fellow veteran Mikhail Youzhny of Russia in three hours, was Federer's 17th win in 17 matches against Youzhny in a rivalry stretching back to 2000.
Five-time US Open champion and third seed Federer had also needed five sets to see off US teenager Frances Tiafoe in the opening round.
"It wasn't always like this," the Swiss player said. "Back then, I used to win or lose in straight sets. But battles can be fun. I feel quite warmed up now."
"Losing that second set was huge for him, tough for me. It really put me in a tough spot there," he added. "I had to come up with something."
World number one Rafael Nadal clawed back after dropping the first set to defeat Japan's 121st-ranked Taro Daniel and also reached the third round here.
The 31-year-old Spaniard won 4-6, 6-3, 6-2, 6-2 over the 24-year-old Daniel, who fell to 0-4 against top-10 rivals.
"It's a very important victory," Nadal said. "It's true I didn't play very well tonight but it's true I'm through to the third round."
There were also wins for Juan Martin Del Potro of Argentina, who defeated Adrian Menendez of Spain, 6-2, 6-3, 7-6(3) while sixth seed Dominic Thiem of Austria beat Taylor Fritz of United States 6-4, 6-4, 4-6, 7-5.