Britain's Andy Murray was knocked out in the second round of the European Open in Antwerp by world number 14 Diego Schwartzman.
The Argentine, 29, came from 4-1 behind to take the first set before winning a tight battle in the second to go through 6-4 7-6 (8-6).
Murray fought back from 4-2 down in the second set to force a tie-break.
Momentum fluctuated in the breaker, with Murray saving one match point before Schwartzman edged home.
Murray - who won this event in 2019 just nine months after pioneering hip resurfacing surgery - edged past Frances Tiafoe in a thrilling first-round match to set up a first-time meeting with Schwartzman.
'Mentally I was poor' - Murray
The former British number one blamed a "poor attitude" for his defeat.
"I didn't make as many good decisions as I would have liked in the second set dealing with adversity," Murray said.
"Mentally I was poor and my attitude was poor on the court. They are two things you can control, if they're not there, that will make the decision-making harder in the matches."
The 34-year-old is scheduled to play at the Erste Bank Open in Vienna next week, before competing in the Stockholm Open in November.
He could also feature at the Rolex Paris Masters as a wildcard or a qualifier.
He added: "There'll be a decision on the final Paris wildcard on Monday. I might even play the qualifiers there.
"Sport is a results business. Play well or poorly, it doesn't matter if you lose matches. You need to be winning.
"That's what I want in the last few tournaments. There are no guarantees the results will come, but I want to win more matches."
'Playing against Murray is a pleasure'
Schwartzman was full of respect for Murray in his post-match comments.
"It was a pleasure to play against Andy," said the Argentine, who reached back-to-back finals in Antwerp in 2016 and 2017.
"We had not played before and he is coming back and every week he is playing better and moving better.
"I have a lot of respect because when I grew up playing tennis, I was watching Roger Federer, Rafael Nadal, Andy Murray and Novak Djokovic and right now, playing against him is a pleasure for me."