Tennis champion Serena Williams (we're pretty sure you've heard of her) is refusing to talk about that shock defeat in the US Open semi-final earlier this week.

Williams lost out to Roberta Vinci on Friday with many describing it as one of the greatest upsets in tennis.

Vinci goes on to face Flavia Pennetta tonight in an all-Italian US Open final, the first between two Italian players since the Open began.

"I don't want to talk about how disappointing this is for me," said Williams in her post-match news conference. The conference lasted just four minutes.

"If you have any other questions I'm open to that."

Here's how Vinci took it...