That is very obviously cursing, because the only reason to say that in the first place is to try to cutely invoke the name of our Lord without actually saying it. WC Fields used to do the same thing in movies; he got away with it sometimes.
It was hard seeing our daughter go down for a profanity charge at such a huge venue, but have to say, she deserved it. It was a play on words and you are right, it meant the same thing. If she had called the umpire a thief and liar it would have been the same outcome as it was for Serena.
Trust me, Serena went through the junior ranks and knew the rules very early on having played tennis all her life. She knew she was going to lose that match, Osaka was playing well above her, so Serena was 8ntentionally trying to change the dynamics of the stadium, thus the match and played the sexist card and “her daughter” card to get the crowd behind her. It was a spectacle.
WC Fields used to do the same thing in movies