Some top players continue to believe Sinner has been given preferential treatment because of his status.

Both the International Tennis Integrity Agency (ITIA) and Wada flatly reject any suggestion that is the case.

But it is clear Sinner - and five-time women's major champion Iga Swiatek, who received a one-month suspension last year after testing positive for heart medication trimetazidine - have benefitted from being able to pay top lawyers to act quickly.

"A majority of the players don't feel that it's fair," said 24-time Grand Slam champion Novak Djokovic.

"It appears that you can almost affect the outcome if you are a top player, if you have access to the top lawyers."

Sinner's lawyer said he thought the swift resolution of the case came down to taking an "unusual" legal approach.

"From day one [Jannik] didn't challenge the science, he didn't challenge the test, didn't challenge the rules," Singer told BBC Sport.

"He accepted, even though it's a trace - it's a billionth of a gram - he accepted that he was liable for what was in his body.

"And so we didn't waste time and money on all of those challenges, which traditionally defence attorneys would throw the kitchen sink at.

"We just focused on the evidence of what actually happened, and when we did that we managed to do that very quickly and demonstrate very plausibly what had happened."

Singer was also aware that the timing of the ban was as good as it could possibly be.

"We can't get away from the fact that you can't choose when these things happen," he said.

"So the fact that Wada approached us and in the next three months there are no Grand Slams, that seemed to me to make their offer more compelling."

Several players believe the timing was suspiciously convenient, with Britain's Liam Broady saying it had impacted Sinner's career as "little as possible".

Asked directly why the deal had come about now, Wenzel insisted it was not taken with the tennis calendar in mind.

"Because of the timing of the Cas proceedings, it happened to be decided on 14 or 15 February, whatever it was, last Friday," said Wenzel. "It was a very late night, and it came into effect immediately, so that is the reason for the timing."

The Professional Tennis Players' Association (PTPA) - an organisation co-founded by Djokovic which aims to increase player power - believes there is a lack of "transparency", "process" and "consistency" in the system.

"Supposed case-by-case discretion is, in fact, merely cover for tailored deals, unfair treatment, and inconsistent rulings," the PTPA said in a statement.

"It's time for change."

Three-time Grand Slam champion Stan Wawrinka, writing on social media, said he did not "believe in a clean sport anymore".