Stefanos Tsitsipas refused to blame his new coaching team after his miserable record at the US Open continued on Wednesday with a second round exit to Swiss qualifier Dominic Stricker.
Seventh seed Tsitsipas, who has never been beyond the third round at Flushing Meadows, slumped to a 7-5, 6-7 (2/7), 6-7 (5/7), 7-6 (8/6), 6-3 defeat in 4hr 4min against his 128th ranked opponent.
It was another disappointing New York campaign for Tsitsipas, who shook up his coaching set-up earlier this month, bringing back Australian Mark Philippoussis while giving his father Apostolos a "break" from coaching duties.
However the 25-year-old from Athens said the coaching changes had little to do with his second round loss, stating the responsibility for defeat was his alone.
"By no means I'm supposed to put any blame on any people or any members of my team," Tsitsipas said.
"Everything on court is under my control and under my talents, and the way I can play this sport are shown out on the court.
"If I'm not able to deliver, then I'm not supposed to be doing well," Tsitsipas added, praising the performance of Stricker.
"His serve was a big weapon that served him really well," Tsitsipas said.
"He's very loose on the serve. If he gets in the zone, he can hit some really good serves."
Leading by two sets to one in the fourth, Tsitsipas had served for the match at 5-3.
But he suffered a service break before Stricker forced a tie-break which he won to send it to a decisive fifth set, ultimately winning the match.
Tsitsipas said he believed it was the first time he'd been broken while serving for the match.
"It hasn't happened to me before," he said. "Usually I'm much tougher mentally, and I have shown it by coming back...today was not the case. I was not able to bounce back after it."
The 21-year-old Stricker will now face France's Benjamin Bonzi, who beat American Christopher Eubanks 7-6 (8/6), 2-6, 6-2, 7-6 (9/7).