When Serena Williams and Maria Sharapova go head-to-head at the French Open tonight, expect there to be sparks.
Williams had a few things to say about Sharapova's new book over the weekend and it's kicked their rivalry up a few notches just in time for their long-awaited rendezvous.
Here's what you need to know.
Williams and Sharapova have been fierce rivals for 14 years
It all started back in 2004 when Sharapova beat Williams in the Wimbledon final.
Sharapova was just 17 years old at the time, and Williams had been the two-time defending champion.
"Obviously it was a disappointing loss to her because she was expected to win," Sharapova told CNN in an interview last year.
"I'm sure she expected to win that match, another Wimbledon final. So I think that disappointment really, it stirred something up. She didn't want to lose to me again."
And she didn't. Williams has dominated ever since then
Williams v Sharapova head-to-head
- Matches played: 21
- Sharapova wins: 2
- Williams wins: 19
- Consecutive Williams wins: 18 and counting
- Sharapova's last win: WTA Championships final, 2004
In fact, their on-court rivalry is so lop-sided it can barely be described as such.
Williams has played a total of 18 matches against Sharapova in the last fourteen years, and won every time.
Meanwhile, Sharapova has taken only three sets off Williams since 2004, and none in their last seven matches since 2013.
Though their off-court rivalry has remained
The two players generally speak with respect for each other's tennis and achievements, but that's where the niceties end.
Both Williams and Sharapova have criticised each other's private lives on several occasions, and in 2013 famously took digs at each other's relationships.
And just this weekend, Williams described Sharapova's autobiography as 'disappointing'
Sharapova's autobiography Unstoppable: My Life so Far was released last year, and speaks extensively about her relationship with Williams.
But at a press conference in Paris over the weekend, Williams described it as "100 per cent hearsay".
She said she was particularly disappointed that Sharapova chose to include a description of her crying in the locker room after her 2004 loss.
"I think what happens there should stay there and shouldn't necessarily be talked about in a not-so-positive way in a book," she said.
"I've cried in the locker room many times after a loss and that's what I've seen a lot of people do. I think it's normal.
"And it's a Wimbledon final — I think it would be more shocking if I wasn't in tears."
So now we wait to see who comes out on top…
Both players are fired up and feel like they have something to prove, with Williams having just returned from maternity leave, and Sharapova from a 15-month doping ban.
If history is anything to go by, Williams is likely to win, but former men's champion Mats Wilander says this is Sharapova's best chance to get back on top.
"Maria has won here twice and her claycourt is really good at the moment. You would assume Serena's not at her best," he said.
As expected, Williams is excited for the challenge.
"I think this will be another test … I think this is one of her best surfaces and she always does really, really well here, so this will be a good opportunity for me to see where I am and hopefully continue to go forward," Williams said.