Serena sees double standard in Zverev case

Twenty-three time grand slam champion Serena Williams says she would have faced far harsher punishment had she engaged in similar behaviour to German Alexander Zverev.

The world No.3 was kicked out of the ATP 500 event in Acapulco for unsportmanlike conduct after he smashed his racket repeatedly against the umpire's chair after a doubles defeat.

Zverev was later fined $40,000 ($A54,000) for the incident, in which he came perilously close to hitting umpire Alessandro Germani.

"There is absolutely a double standard," former world No.1 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 behaviour" during her semi-final against eventual champion Kim Clijsters at the US 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."