Rejuvenated at age 32, Lleyton Hewitt was two points away from reaching the US Open quarter-finals for the first time since 2006.
Mikhail Youzhny would not let the tournament's 2001 champion close out the win.
The 21st-seeded Youzhny finished the back-and-forth, nearly four-hour match strongly, taking the final five games and coming back to beat Hewitt 6-3, 3-6, 6-7 (3), 6-4, 7-5 in the fourth round Tuesday.
Hewitt won more total points, 146-145. Wearing his trademark backward-turned white baseball cap, he got within two points of winning while ahead 5-2, then served for the match at 5-3, before fading down the stretch.
Youzhny's best Grand Slam showings have come at Flushing Meadows, where he made the semifinals in 2006 and 2010 and also lost in the first round each of the past two years.
Two-time major champion Hewitt had been 7-0 in fourth-round matches in New York, but he hadn't even been that far in seven years. A former No. 1-ranked player who is currently 66th after a series of foot and hip injuries, Hewitt last got to the quarterfinals of any Grand Slam tournament at Wimbledon in 2009.
Russia's Youzhny, who is 31, will face No. 1 Novak Djokovic or 43rd-ranked Marcel Granollers in the quarterfinals.
"I have to play well,'' Youzhny said with a chuckle, figuring he'll wind up against six-time major champion Djokovic.
"First of all,'' Youzhny added, "I have to recover after this match.''
Every time it appeared one man or the other was pulling away, the other got right back into it.
Hewitt trailed by a set and a break before going ahead 2-1 in sets. Then he grabbed 11 of the first 12 points to start the fourth, going up 3-0 and 4-1. But Youzhny responded with a six-game run. In the fifth set, Youzhny broke in the first game by making a long sprint, then sliding wide of the doubles alley, for a backhand winner. Sticking to the match's pattern, Hewitt broke right back.
In 80-degrees Fahrenheit (26.67-degrees Celsius) heat, both Hewitt and Youzhny often appeared content to hang out at the baseline for lengthy exchanges, often slicing backhands or simply placing forehands in the middle of the court. Points would last 10, 20, 30 strokes.
Back and forth they went, two of 12 active men who have made it at least as far as the quarterfinals at all four major tennis tournaments.
At 2-2l in the fifth set, Hewitt tore some skin off his left elbow while diving on the hard court for a shot. After Youzhny won the point to get to 15-30 on Hewitt's serve, play was halted for a medical timeout while a trainer treated the bloody scrape on the Australian's arm.
Later in that game, Youzhny had a break point to nose ahead, but he missed a forehand, and Hewitt wound up holding.
What appeared to be the final momentum swing came in the very next game, when Youzhny was a point away from making it 3-3, before coming undone. He put a forehand into the net, missed a backhand, then double-faulted to hand Hewitt a 4-2 lead.
Hewitt then was two points away from victory at 5-2, but Youzhny held serve there. With Hewitt serving for the win at 5-3, Youzhny earned a break point by stretching for a volley winner with both players up at the net. Hewitt then missed a backhand to make it 5-4.
That was part of a stretch in which Youzhny took 12 of 13 points. When Hewitt pushed a forehand long to get broken again, Youzhny led 6-5, and there would be no more shifts.
Hewitt's renaissance at this tournament included a five-set, four-hour victory over 2009 U.S. Open champion and sixth-seeded Juan Martin del Potro in the second round. That was the first time Hewitt had beaten a player ranked in the top 10 at Flushing Meadows since upsetting 14-time major champion Pete Sampras in the 2001 final.
Perhaps because of name recognition, Hewitt generally received more of the crowd's support at Louis Armstrong Stadium.
When Youzhny broke to 4-3 in the fourth set with a backhand winner, he held his arms wide and palms up and screamed, "Come on!''
"I understand. It was fine. The crowd was not against me. It was for Lleyton more,'' Youzhny said during an on-court interview.
Then, thanking those spectators who were cheering for him, Youzhny said, "Maybe your power gave me the chance to beat Lleyton today.''