Eccentric Frenchman Gael Monfils reached his second US Open quarter-final on Tuesday, stunning seventh-seeded Grigor Dimitrov 7-5, 7-6 (8/6), 7-5.
Crowd favourite Monfils overcame a dramatic loss of composure in the second set to book a last-eight date with either five-time champion Roger Federer or Spain's Roberto Bautista Agut.
"It's my first ever win on the Ashe stadium which is great," said the 20th seed who also reached the quarter-finals in 2010.
"I love to play in New York. There is so much energy and it helps me deliver my game."
Monfils also admitted that playing without a coach seemed to be working for him.
"I guess I should stay this way," added the French star who will be looking to equal his best Grand Slam performance of a 2008 run to the French Open semi-finals.
Wimbledon semi-finalist Dimitrov was hoping to reach his third quarter-final at the majors this year but despite occasional breath-taking shot-making, he was undone by 38 unforced errors.
Monfils had celebrated his 28th birthday on Monday and the feelgood factor took him racing through the first set on the back of a break for a 6-5 lead.
The Frenchman was another break to the good at 4-2 in the second before he got embroiled in a brief war of words seemingly directed at Dimitrov's player box.
Dimitrov is coached by Roger Rasheed who had handled Monfils until they split in 2011.
Still seething, the Parisian then surrendered a break point by not returning the ball in the eighth game.
But he bounced back in impressive style, saving two set points in the tiebreak before winning four points in a row to open a two sets to love lead.
Wimbledon semi-finalist Dimitrov, who had never won a match in New York on his three previous visits, was facing having to come back from two sets to love down for the first time in his career.
He then added to the drama, albeit unintentionally, when he had to leave the court to replace his shoes which came apart early in the third set.
But his luck didn't change and his campaign was over when he served up his fourth double fault of the tie.
Later Tuesday, Federer looks for a 25th win in 26 night time matches when he faces Bautista Agut for the first time.
Second seeded Federer is bidding to reach his 10th US Open quarter-final in 11 years while world number 19 Bautista Agut is seeking a first appearance in the last eight at a major.
Czech sixth seed Tomas Berdych, a semi-finalist in 2012, faces Austria's Dominic Thiem for the first time.
World number 45 Thiem, who turns 21 on Wednesday, is the youngest player left in the men's event and is looking to become the first Austrian since Thomas Muster in 1996 to make the quarter-finals in New York.
The winner of that clash will face either 14th seed Marin Cilic of Croatia or French 26th seed Gilles Simon.
Cilic is aiming for a third US Open quarter-final but he has lost all four meetings with Simon including in the Australian Open second round this year.
Simon has previously made the quarter-finals at a major just once, in Australia in 2009.
The quarter-finals in the top half of the draw take place Wednesday with world number one Novak Djokovic taking on fellow former champion Andy Murray and Australian Open winner Stan Wawrinka facing Kei Nishikori of Japan.
Nishikori is the first Japanese man since Zenzo Shimidzu in 1922 to reach the last-eight but he did it the hard way.
His fourth round win over Milos Raonic ended at 2:26 a.m. Tuesday (0626GMT) to tie the latest finish in US Open history.