A little over a month after Serena Williams' bid for a seventh US Open singles title ended in controversy, the longtime tennis player's coach has made a case for all major tournaments to allow on-court coaching.

Williams, of course, came up short against Naomi Osaka during September's women's final following a dispute with chair umpire Carlos Ramos. Penalized for apparently receiving illegal hand signals from her coach, the 23-time Grand Slam champion then earned additional punishment -- not to mention a $17,000 fine -- for smashing her racket and chastising Ramos as a "thief."

Now, in a column for Britain's Tennishead magazine, the same coach behind Williams' alleged violations is suggesting that on-court coaching shouldn't be a violation at all.

"One very good thing has happened as a consequence of Serena Williams' experience in the US Open final: People throughout tennis are again discussing the whole issue of on-court coaching," wrote Patrick Mouratoglou, Williams' coach since 2012. "At the moment we're in the worst of all worlds. On-court coaching is clearly widespread, but it is unstructured, players are occasionally given code violations for it and TV viewers are given no insight into what the coaches are telling their players."

Williams has publicly accused Ramos of sexism for wrongly accusing her of receiving coaching on the US Open court, so it's mildly surprising that Mouratoglou, in his most prominent comments on the match to date, didn't necessarily defend Williams as much as he pleaded for the alleged wrongdoing to be permitted. On the other hand, as Mouratgolou's comments suggest, perhaps the bigger US Open takeaway isn't what happened to Williams as opposed to a widespread flaw in coaching regulations.

"It's a very basic truth that the vast majority of tennis coaches are actually coaching on court, despite the rules," he said. "Occasionally the players are punished for it, but for the most part they are not."

Under current tennis rules, as CNN's Danielle Rossingh noted, on-court coaching has been permitted on an experimental basis during qualifying and junior events at the US Open, while the women's WTA Tour "allows women to talk to their coach during one changeover per set." The men's ATP World Tour and all four tennis majors, however, prohibit such coaching.

"I have never understood why tennis is just about the only sport in which coaching during matches is not allowed," Mouratoglou wrote.