This is their first meeting on green clay, with the sisters splitting the two matches the two have played on red clay (2002 Roland Garros final w. Serena and 1998 Rome quarterfinal w. Venus).
Serena is the defending champion here and won last week's Key Biscayne title for a record 6th title, coming back from a set and break down to demolish her arch-nemesis Maria Sharapova for the 11th consecutive time.
Both sisters had to play two matches yesterday, with Venus beating fellow Americans Varvara Lepchenko 6-2 4-6 6-2 in the 3rd round and Madison Keys 6-4 6-4 in the quarterfinals a few hours later. Serena beat American qualifier Mallory Burdette (who?) 6-4 6-2 in the 3rd round and 2012 Family Circle Cup finalist Lucie Safarova 6-4 6-1.
The winner of the Williams showdown will face either Stefanie Voegele or Jelena Jankovic in the final. Jankovic won her 500th WTA tour match, while Voegele upset Carolina Wozniacki 3-6 6-4 6-3.
ESPN2 will broadcast today's match between Venus and Serena at 1pm EDT.
MadProfessah's prediction: Serena.