HEAD TO HEAD

Serena leads it 11-2. She has won their last nine matches dating back to the 2004 WTA Championships and has taken the last 12 sets from the Russian. Their last two matches were at the 2012 WTA Championships (a 6-4, 6-3 victory for Ms. Williams) and the 2013 Doha semis (a 6-3, 6-2 win for Serena). Those matches were competitive during Sharapova service games, but not as much during Serena