Roger Federer was taken to five sets for the second time in three days before overcoming Russia's Mikhail Youzhny at the US Open.
The five-time champion was two sets to one down but eventually came through 6-1 6-7 (3-7) 4-6 6-4 6-2 in New York.
Federer has now won all 17 matches against Youzhny, a year younger at 35, since the pair first met in 2000.
Top seed Rafael Nadal required four sets to see off Japan's Taro Daniel in the night session.
The Spaniard, 31, trailed by a set and a break before two fizzing forehands turned the second set around and he went on to win 4-6 6-3 6-2 6-2.
"It's true that I didn't play very well tonight but at the same time it's true that I'm through to the next round," said the two-time champion.