MADRID, Spain - Li Na is sitting on 499 wins entering another showdown with Maria Sharapova at the Mutua Madrid Open, while Serena Williams now has 650 under her belt as she prepares to do battle with Petra Kvitova.
 Li Na (CHN #2) vs.  Maria Sharapova (RUS #9)
Head-to-head: Sharapova leads 9-5
Li Na and Maria Sharapova have had a back-and-forth history, with Sharapova winning the first five, Li the next four all in straight sets and Sharapova four of the most recent five. She is also the WTA's active leader in clay court win percentage, so even though she is ranked seven spots lower than Li, Sharapova may be the favorite to many to come through this quarterfinal encounter. She has an 86-19 record in WTA quarterfinals.
Li, who is 24-3 on the year, has only failed to make the semifinals of one event this season - Doha. A win would put her into her second Madrid semifinal, having gotten that far in 2011. Sharapova's best result here is a runner-up showing last year. Both players are coming off wins over Top 20 opponents, Li in three sets over Sloane Stephens and Sharapova in straight sets over Samantha Stosur.
 Serena Williams (USA #1) vs.  Petra Kvitova (CZE #6)
Head-to-head: Williams leads 5-0
Serena Williams and Petra Kvitova both are obviously comfortable on the courts of Madrid, having combined to win the last three titles here - Kvitova in 2011 and Williams in 2012 and 2013. In fact, Williams carries a 15-match Madrid win streak into this contest. A third straight title would be the second time she has accomplished that feat, having done so in Miami from 2002 to 2004. She also needs to win to keep alive her pursuit of her 60th WTA title.
Williams has yet to drop more than three games in a set this week, and her latest victory made her one of 11 players with at least 650 in her career. In fact, a defeat of Kvitova would tie her with sister Venus for 10th place on the all-time list. She has lost only one set to Kvitova, though this will be their first encounter on clay.
Kvitova needed three sets to get through each of her first two matches here, but recorded a comfortable straight set defeat of fellow Czech Lucie Safarova in the third round. She is seeking her 13th Top 5 win and third over a reigning World No.1, having previously beaten Dinara Safina at the 2009 US Open and Caroline Wozniacki at the 2011 WTA Championships.
 Simona Halep (ROU #5) vs.  Ana Ivanovic (SRB #12)
Head-to-head: Tied 1-1
After having lost in the first round of Madrid in her first three main draw appearances here, Simona Halep has fared much better this year - most recently recording a three set triumph over No.15 seed Sabine Lisicki to make the quarterfinals. That made her 6-1 against Top 20 opponents this year. Interestingly enough, Halep has either lost her opener or at least reached the quarterfinals in all of her tournaments this season.
As for Ivanovic, she is the only player left besides Williams yet to surrender a set and is coming off an especially dominant 6-1, 6-2 rout of Anastasia Pavlyuchenkova - her 12th win in her last 13 matches. If she makes it 13 of 14, that will put her into the semifinals here for the second consecutive year and will keep alive her hopes of re-entering the Top 10. She is seeking her 15th Top 5 win, with her most recent actually coming against Halep in Fed Cup World Group II play.
Read more details and stats about Thursday's match-ups in our Match Notes.