Alex de Minaur took aim at the "never-ending" tennis schedule on Thursday after blowing a two-set lead in his second-round loss to Alexander Bublik at the French Open.
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The Australian ninth seed had reached the quarterfinals at each of the past four Grand Slams but he ran out of steam against Bublik, who rallied to win 2-6, 2-6, 6-4, 6-3, 6-2.
"Obviously not a good day at the office," lamented De Minaur.
"One of those matches that kind of just slipped away without a whole lot of meaning."
De Minaur fell victim to the mercurial Kazakh's exceptional shotmaking as his clay-court season ended in disappointment and with the 26-year-old needing to recharge.
"Look, I'm just tired. I'm tired mentally. I'm a little bit burnt out, if anything. A lot of tennis being played," he said.
"I think I lost that one. Looking back at my Grand Slam career, I can't think of another match where I felt this way and I ended up losing a match that I probably by all means shouldn't have.
"Look, not to take credit away from Bublik, he's extremely dangerous, but saying that, I was also two sets to love up. This is a match that, yeah, I win 99.9 per cent of the time."
De Minaur echoed the view of Casper Ruud, the two-time French Open runner-up who blasted the ATP's ranking system after he lost in the second round on Wednesday.
World No 8 Ruud compared it to "a rat race" which forces players to compete with injuries, as he was hindered by a knee issue in his to loss Nuno Borges.
De Minaur missed three Masters 1000 events in the second half of last year due to injury and took just two days off after the Davis Cup in November before starting preparations for the new season.
"It's just never ending," he said of the schedule.
"No one's got a solution. But the solution is simple: you shorten the schedule, right?
"Because what's going to happen is players' careers are going to get shorter and shorter because they're just going to burn out mentally. There's just too much tennis."