Agnieszka Radwanska (POL #3) vs.  Dominika Cibulkova (SVK #11)
Head-to-head: Radwanska leads 5-2
Agnieszka Radwanska's recent history in Miami is superb, having won 13 of her last 14 matches here. The 2012 Sony Open Tennis titlist is the only former champion still in the draw besides six-time winner Serena Williams. A triumph over Dominika Cibulkova would also be her ninth win in her last 10 matches dating back to her run to the Indian Wells final.
Cibulkova is no stranger to Top 5 wins, with 12 under her belt. But a 13th would be extra special, in that it would ensure she cracks the Top 10 on the new rankings.
Their series has been a wild one, with Radwanska winning the first four matches, including a 60 60 rout in the 2013 Sydney final. But Cibulkova has won two of the last three, including the 2013 Stanford final and a 2014 Australian Open semifinal in which the Slovak dropped just three games.
 Li Na (CHN #2) vs.  Caroline Wozniacki (DEN #18)
Head-to-head: Li leads 3-2
While Li Na surrendered just two games in her fourth round defeat of Carla Suárez Navarro, quarterfinal foe Caroline Wozniacki actually dropped one less in her fourth round win over Varvara Lepchenko. And that came two days after the Dane only allowed Sloane Stephens one game. But while Wozniacki may be playing better than anyone this fortnight, Li is having the stronger season overall, with her two titles leading the WTA and her 19 match wins tied for the WTA lead. If she records her 20th win on Wednesday, she will be China's first Miami semifinalist.
Wozniacki is looking for her seventh Top 5 win and her first since Brussels in 2011. If she pulls it off, it will match her best career win, which came over No.2 Vera Zvonareva at the WTA Championships in 2010. It would also put her into the Miami semifinals for the second time, having also gotten that far in 2012.
The series between the two has consisted of Wozniacki winning the first match-up, Li the next three and Wozniacki the most recent. Four of the matches have gone three sets, and strangely enough three of those were won by the player who lost the first set.
Find the listings for Wednesday's play on the WTA TV developed by Xerox.