Serena Williams (USA #1) vs.  Angelique Kerber (GER #9)
Head-to-head: Williams leads 3-1
After being tested in each of her first two matches this fortnight, Serena Williams improved to 64-7 here with a routine 63 61 defeat of Coco Vandeweghe on Monday. That also put the six-time Miami champion into the quarterfinals for the 13th time in her 14 outings here, the lone exception being a fourth round showing in 2000.
After coming into Miami on a three match losing streak, Angelique Kerber has made it to the quarterfinals here for the first time. It hasn't been easy, though, as she was extended to three sets in the second round and fourth round. Her second round triumph over Peng Shuai was especially challenging, as she had to rally from a 5-2 third set deficit. If she is able to beat Williams for the second time, it will be her seventh Top 5 win and her first in seven meetings against a reigning World No.1.
 Maria Sharapova (RUS #7) vs.  Petra Kvitova (CZE #8)
Head-to-head: Sharapova leads 4-2
Though she has been pushed to three sets in the last two rounds, Maria Sharapova finds herself in the latter stages of the Sony Open Tennis once again. She has now won 18 of her last 21 matches here, and if she records two more, that will put her in the Miami final for the fourth straight time and sixth time overall.
Sharapova's opponent on Tuesday, Petra Kvitova, will be contesting her first Sony Open Tennis quarterfinal. The Czech certainly hopes she is in similar form as she was in the latter stages of her fourth round clash with Ana Ivanovic, in which she did not lose a game after dropping the first set.
Kvitova and Sharapova have played on every surface, with Kvitova winning their biggest match in the 2011 Wimbledon final but Sharapova victorious in their last three encounters - including two Grand Slam semifinals.
Find the listings for Tuesday's play on the WTA TV developed by Xerox.