Today at 10:00 a.m. ET on ESPN No. 1 women's tennis player Serena Williams will face off against No. 4 Maria Sharapova, one of the biggest stars in the sport, but one who has been unable to solve Williams for a long time. Live stream the highly anticipated clash for free by clicking this link.

Sharapova is one of the most respected women's tennis players of all-time, but Serena Williams displays no respect on the court. Sharapova's dropped 16 straight matches vs. Williams, and has a 2-17 record overall against her.

"It's kind of similar to where I was with Roger [Federer]," Andy Roddick, former men's tennis star said. "I didn't have a great record. But it's not about the last 10 years, it's about one match. You don't have to be better than her forever, you just have to be better than her for one day."

Williams' coach disagreed with Roddick, and doesn't think Sharapova has some kind of mental barrier precluding her from overcoming Williams.

"She does not have a mental block against Serena," Patrick Mouratoglou said. "Serena simply plays tennis much better than she does. For me, [Victoria] Azarenka [whom Williams defeated in a three-set quarterfinal Tuesday] is much better than Sharapova. There's no discussion. Sharapova is a great champion. She has great qualities. She fights incredibly and has tremendous mental strength. But at some stage, her level of play hits a ceiling."

Williams has struggled at various points in this year's Wimbledon. There was a hairy second set in the third round vs. Heather Watson of the U.K., and a poor first set against Victoria Azarenka for Sharapova to point to. Then again, she also rebounded from both of those poor sets with dominance.