Andy Murray appeared to declare that retirement could be close during his Qatar Open defeat to Jakub Mensik on Wednesday.
The three-time Grand Slam champion was picked up by TV cameras saying 'This game's not for me anymore' during the second round clash.
Murray won his first match since last October on Tuesday, beating France's Alexandre Muller in straight sets in the first round.
He will have harboured hopes of going deep into the competition in Doha after an extremely difficult few months on the court.
Andy Murray has appeared to suggest he could soon retire from tennis
Sky Sports
He dropped the first set against 18-year-old Czech star Mensik and was often seen venting his frustration towards his coaching team.
Murray had break point at 5-5 in the second set but saw his shot hit the top of the net and bounce back towards him.
The TV cameras zoomed in on the 36-year-old's face after he lost the point as he again aimed anger towards coach Jonny O'Mara.
This time Murray was seen saying: "This game's not for me anymore. It's not for me anymore, this game."
Murray went on to win the second set via a tie-break but lost the match in the same manner in the decider, eventually going down 7-6, 6-7, 7-6.
He has repeatedly fought off any claims that he should retire despite his wretched run of form.
He has previously stated that 2024 could be his final season as a professional but he wants to go out on his own terms.
Murray has struggled with injuries over the last few years and had crashed out in the first round of his previous five tournaments before this week.
He angrily hit back at a journalist last month, who suggested Murray was tarnishing his legacy by continuing to play.
Murray responded on X: "Tarnishing my legacy? Do me a favour. I’m in a terrible moment right now I’ll give you that.
"Most people would quit and give up in my situation right now. But I’m not most people and my mind works differently. I won’t quit.
"I will keep fighting and working to produce the performances I know I’m capable of."
Speaking on Monday, he again confirmed that he will not listen to what any of his doubters say.
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Murray said: "When I was in my early 20s, I would have mainly young fans that would come up to you and ask for autographs, now I get more older people, whose bodies are falling apart.
"They are kind of like: 'It's great that you keep going, it's inspired me to get out and keep training', so the demographic has changed a little bit.
"It's nice, I can do whatever I want. I don't have to do what fans, journalists or anyone is telling me to do.
"Qualifying for all these tournaments on my right, on my ranking and all the matches that I've won, I want to keep playing just now. So I'm not going to stop."
Andy Murray said 'this game's not for me anymore' during his Qatar Open loss
Sky Sports
However, Murray's latest outburst may suggest that he is coming around to the idea of calling it a day.
He fought back admirably to force the third set to a tie-break against Mensik.
However, Murray's anger got the better of him as he smashed his racket in frustration as his teenage opponent saw out the win.