Paris - Rafael Nadal blasted French Open umpire Carlos Ramos on Sunday for treating him like a "machine" and suggested he was being unfairly targeted in an effort to speed up play.
Nadal reached a record-equalling 11th Roland Garros quarter-final with a 6-1, 6-2, 6-2 win over Spanish compatriot Roberto Bautista Agut.
But his joy at matching Roger Federer's mark for last-eight appearances in Paris was overshadowed by an astonishing broadside at Ramos.
The umpire had warned the 31-year-old in the first set for slow play and again in the third before deciding to dock Nadal a first serve.
"If you want to play well, you have to let players breathe a little. We're not machines that cannot think. That's my viewpoint," said Nadal, who repeatedly falls foul of the rule which stipulates a maximum 25 seconds between points.
"What else can I say? I'm telling you this with some sadness, because I don't want to have any problems.
"But this umpire is, I think, trying, in a certain way, to look for my faults, my errors."
The 14-time major winner believes that some umpires are stricter than others who may afford a player more leeway especially in the red-hot atmosphere of a Grand Slam.
"Theoretically the umpires are here to analyze the match and they are not here to use the stopwatch, otherwise we should have a stopwatch on the court," added Nadal, warming to his theme.
"That's the whole point. Some dictate things or give their calls in a certain way. Other umpires have different styles."
Despite a career-long habit of over-stepping the time allowance -- a situation not helped by his idiosyncratic plucking at his shorts and smoothing of his eyebrows -- Nadal insisted he will not change.
"I told him that he will have to give me many warnings, because if I have not yet grabbed my towel, that he's going to give me a warning," he added.
Vanquished opponent Bautista Agut backed Nadal in his spat with Ramos.
"Rafa and I need to play a lot of points. We need to run around a lot. Having the pressure of the umpires is something we don't really need," said the 29-year-old.
"I don't think I really agree with that rule."
The fall-out with Ramos meant that Nadal's smooth progress to the last eight became a sideshow.
He has dropped just 20 games in four rounds so far, just one more than he lost at the same stage in 2012, as he attempts to become the first player to win the same Slam 10 times.
Nadal will face fellow Spaniard Pablo Carreno Busta who stunned fifth-seeded Milos Raonic 4-6, 7-6 (7/2), 6-7 (6/8), 6-4, 8-6.
Carreno Busta, the 20th seed, will be playing in his first Slam quarter-final at the age of 25.
But he did it the hard way, needing seven match points to seal victory over the Canadian after 4hr 17min on Court One.