Russian 21st seed Mikhail Youzhny mounted two stunning comebacks to defeat 2001 champion Lleyton Hewitt 6-3, 3-6, 6-7 (3/7), 6-4, 7-5 and reach the US Open quarter-finals on Tuesday.
Youzhny, a semi-finalist in 2006 and 2010, was two sets to one down and trailed 4-1 in the fourth set and 5-2 in the fifth before battling back to book a last-eight clash against either top seed Novak Djokovic or unseeded Spaniard Marcel Granollers.
In an enthralling clash, which was just two minutes short of four hours on the same Louis Armstrong court which had swallowed up five-time champion Roger Federer the day before, Youzhny celebrated just his second win in seven meetings over the Australian.
The 32-year-old Hewitt, the oldest man left in the tournament, was bidding to make the last-eight in New York for the first time since 2006, having defeated 2009 champion Juan Martin Del Potro in the second round.
But he was left to rue his failure to serve out the match at 5-3 in the decider after having recovered from losing the first set and being a break down in the second.
Youzhny, who famously defeated Rafael Nadal in the fourth round in 2006, hit 47 winners while commiting 63 unforced errors with Hewitt, now the world number 66, finishing with 55 winners and 54 unforced errors.
However, he served up nine double faults at crucial times in his 200th Grand Slam match, which proved a dramatic affair with even a 46-shot rally being exchanged in the third set.
"It was a great atmosphere and a joy to play here. I fought back in the fourth and fifth sets because I didn't want to be heading home just yet," said 31-year-old Youzhny.
"The crowd wasn't against me but for Lleyton. It gave me power to keep coming back.
"Lleyton is a great player. When he is on the court he always fights. He's still a top player and can beat top players like Del Potro. It was very tough for me to beat him for just the second time."
Later Tuesday, world number one Djokovic attempts to reach an 18th successive Grand Slam quarter-final when he faces Spanish world number 43 Marcel Granollers, who has yet to reach the last eight of a major.
Djokovic, the champion in 2011, is bidding to make the final for a fourth successive seeason.
The top-seeded Serb has yet to drop a set at the tournament while Granollers, one of four Spaniards in the last 16, has played three five-set matches, spending almost 10 hours on court, twice as long as Djokovic.
Defending champion Andy Murray, the third seed, tackles unseeded Denis Istomin of Uzbekistan, the world number 65, who has never beaten a top 10 player in six attempts.
Fifth seeded Czech Tomas Berdych trails Swiss ninth seed Stanislas Wawrinka 6-5 ahead of their last-16 clash.
Berdych made the semi-finals in 2012 after knocking out Roger Federer in the quarter-finals.