The former world number one lost in straight sets to Naomi Osaka in a bizarre final, where she received three code violations and was penalised a game.
It was the first violation for coaching that set off Williams, who would eventually label chair umpire Carlos Ramos a “thief”, a “liar” and “sexist”. Following the final, Mouratoglou admitted to coaching from the players box, saying he made a gesture but that “everyone does it”.
But Williams remains resolute in her claims of innocence.
“I just don’t understand what he was talking about,” the 23-time grand slam winner told Australia’s Network Ten show The Sunday Project.
“I asked him ‘what are you talking about you were coaching? We don’t have signals, we’ve never had signals’.
“He said he made a motion. So I was like ‘you made a motion and now you told people that you’re coaching me – that doesn’t make sense, why would you say that?’
“I was on the other side. I didn’t see the motion. It was just a really confusing moment, I think, for him.
“What I’m trying to do most of all is to recover from that and move on.”
BBC Sport revealed that during the show, Williams was asked if she regretted breaking her racquet – the second code violation – but she did not answer.
The 36-year-old was fined over $17 000 for the code violations.