TWENTY-THREE time Grand Slam champion Serena Williams said she would have faced far harsher punishment had she engaged in similar behavior to German Alexander Zverev, who was thrown out of a tournament last month for unsportsmanlike conduct.

The world number three was kicked out of the ATP 500 event in Acapulco after he smashed his racket repeatedly against the umpire's chair after a doubles defeat. 

Zverev was later fined $40,000 for the incident, in which he came perilously close to hitting umpire Alessandro Germani. 

"There is absolutely a double standard," former world number one Williams told CNN reporter Christiane Amanpour. "I would probably be in jail if I did that - like, literally, no joke.

"I was actually on probation once," she added, but declined with a chuckle to discuss further when Amanpour inquired about the incident.

In 2009, the Grand Slam committee placed Williams on probation for two years and fined her $175,000 for a "major offence of aggravated behavior" during her semi-final against eventual champion Kim Clijsters at the U.S. Open.

"You see that (double standard) when you see other things happening on the tour, like, 'wait - if I had done that? Hmm,'" said Williams.

"But it's okay. At the end of the day I am who I am and I love who I am."