As Rafael Nadal prepares to defend his French Open crown in Paris next week, his time-wasting is making a mockery of the tennis rulebook. The Daily Telegraph can reveal that Carlos Bernardes, the last umpire to seriously challenge Nadal on this point, has been withdrawn from Nadal's matches since and is unlikely to officiate him at Roland Garros.
The bad blood between the two dates back to Feb 22, and the semi-final of the Rio Open. Bernardes followed the letter of the law by handing Nadal two time violation penalties for exceeding the 25-second limit between points, the second of which cost him a first serve. In a Spanish exchange captured by the courtside microphones, a furious Nadal then told Bernardes: "I will make sure that you don't arbitrate me anymore." Clearly agitated, he went on to lose to Fabio Fognini in three sets.
Nadal has played 24 matches since, on a men's tour which has nine "elite" umpires. Bernardes, who ranks highly within that group, would have been available for 20 of them. Significantly, though, he has not been called upon.
The Association of Tennis Professionals, which runs the tour, told The Telegraph "a number of factors are taken into consideration in the [umpire] selection process, including badge qualifications, nationality, as well as any previous history or incidents".
It is hardly news that umpires tend to be kept away from players with whom they have had a recent disagreement.
In most cases, however, the row tends to be over a one-off issue such as a line call or a double bounce. Former ATP umpire Richard Ings told The Telegraph that, during the 1990s, he had not officiated any matches involving Ivan Lendl for a year after a bust-up over an overrule on match point.
What makes the Nadal situation different is that his poor timekeeping has been a constant issue throughout his career; an issue that the authorities have purported to address, without ever actually doing so.
At the beginning of 2013, the ATP announced it was trying to crack down on violations of the 25-second rule, in a response to the six-hour Australian Open final between Nadal and his great rival Novak Djokovic the previous year.
But here we have an umpire who has actually applied the rule, only to be kept away from Nadal's matches since. After such a precedent, it is hardly surprising Nadal has not been penalised by the loss of a first serve since that day in Rio. He has received a first warning - the shot across the bows - on several occasions in the past three months, but nothing substantive.
ATP umpires might recall the case of Jeremy Shales, the British official who had a huge falling-out with Jimmy Connors at the Lipton Championships in 1986, then found that his contract was not renewed the following year.
The incident highlighted a fundamental weakness in a sport where the officials are effectively employed by the players. (The ATP is constituted as a 50-50 alliance between players and tournaments.)
Nadal was asked about the Rio situation in a press conference a few weeks later in Indian Wells. Bernardes was "not fair enough the last couple of times", he replied.
"He has been putting more pressure on me than other umpires. For me it is not right [when] you see players doing bad words, breaking rackets, doing shows on court, and that's less important than five seconds late, six seconds late? Sorry, I cannot accept that, I cannot say that's right.
"I know I am little bit slow, but in Rio the weather conditions ...I finish every match and my hand was like I have been two hours in the jacuzzi."
It is true that tennis has a variety of rules which are only patchily enforced, the "audible obscenity" call standing high on the list. In a sport that treasures its gentlemanly image, umpires are reluctant to cause a scene. In a typical incident in Estoril last month, Nick Kyrgios hit a ball out of the stadium - "ball abuse" - during a final-set tie-break, and should technically have lost the match there and then, as he had already been docked a point. Yet umpire Fergus Murphy chose to turn a blind eye.
Still, as Sky analyst Barry Cowan points out: "Rules are rules and this isn't a grey area. We often see Nadal getting a first warning, and it's usually on a big point - when he's serving for the set perhaps - as if the umpires want so say, 'Hey, we're getting tough here'. But then they don't take the next step. Whereas when Marcel Granollers cramped up in a match in Madrid the other day and couldn't get into position, bang: point gone. We heard Dimitry Tursunov say it during a match last year: it's one rule for Rafa and one for everyone else."
Nadal is generally perceived to have quickened up his pace of play slightly in the last couple of seasons. He now takes only one towel to the back of the court for sweat removal, where it used to be two. But he still remains the man most likely to spill over the stipulated 25 seconds.
In Rome last week, he was regularly arriving at the service line after 22 seconds had already elapsed, and only then embarking on his characteristic series of tics: the plucking of the shorts, the touch of the nose and the eyebrows.
ATP officials are understood to have passed a message on to his coach and uncle, Toni Nadal, insisting that he needs to be up at the service line more quickly.
All eyes will now be on Nadal's matches in Paris next week. In theory, the grand slams operate a stricter policy of 20 seconds between points. But in practice - as in so many instances in this often quixotic sport - the rule is rarely enforced.