World tennis chiefs need to clarify their position on in-match coaching to prevent another incident after Serena Williams’ US Open meltdown, the head of the Australian Open said Monday.

The 23-time Grand Slam champion was warned for receiving coaching from the players’ box during Saturday’s final, triggering a row with the chair umpire in her 6-2, 6-4 loss to Naomi Osaka.

Williams was docked a point for smashing a racquet and she called umpire Carlos Ramos a “thief” and a “liar”, an outburst for which she was sanctioned a game at a critical juncture in the second set.

Australian Open tournament director Craig Tiley said coaching, which is allowed a Women’s Tennis Association events but not at men’s or Grand Slam tournaments, remained a grey area.

“It all centred around coaching... the sport has to really get itself sorted out on what it does with coaching,” he told reporters.

“Are we going to have coaching? Are we not going to have coaching? What is it going to look like?

“The sport needs to get together and sort it out. Once that’s sorted out, we don’t have the issue.”

Williams’ coach Patrick Mouratoglou admitted that he was coaching – although it was not clear if she saw his gestures – and insisted the practice was common.

“Yes, I was coaching just like everybody else. We have to stop this hypocrisy,” he said.

WTA Tour chief executive Steve Simon has also said the sport should examine the rules on coaching, noting that his organisation allows on-court coaching during regular tour events if a player requests it.

Despite the furore, Tiley said it should not overshadow the emergence of Osaka.

He called her performance “unbelievable” and forecast a major boon for the Australian Open, which bills itself as the Grand Slam of the Asia-Pacific.

“For us as the Grand Slam in the Asia-Pacific, to have a player from Japan, the first time ever a player from Japan to win that title in the fashion that she did, is particularly exciting,” he said.

“We all see how the Japanese fans flock to see Kei Nishikori.

“It’s going to have a significant positive impact on our Open, on our fans.”