MIAMI, FL, USA - Day 10 at the Sony Open Tennis will see all four semifinalists in action. First up are Maria Sharapova and Jelena Jankovic, before Serena Williams takes on reigning champion Agnieszka Radwanska in the evening session.
 Maria Sharapova (RUS #2) vs.  Jelena Jankovic (SRB #24)
Head-to-head: Sharapova leads 6-1
While calling a former World No.1 a surprise package may seem something of a misnomer, it is hard to deny that Jelena Jankovic is the least predictable of the Crandon Park semifinalists. Certainly, few would have foretold her run to the last four after her life and death battle with American wildcard Victoria Duval in the second round. But since then she has grown in confidence, defeating Nadia Petrova, Sorana Cirstea and in the last round outlasting the high-flying Roberta Vinci.
Her reward for this obdurate display is a meeting with recent Indian Wells champion Maria Sharapova. Jankovic will need to produce another spectacular defensive display to disarm the Russian, who broke down the WTA's sturdiest of walls during her absorbing quarterfinal with Sara Errani.
Sharapova, a four-time runner-up at Crandon Park, has enjoyed an impressive start to 2013, with 18 wins already to her name. Unfortunately, for Jankovic - who is bidding to become just the fourth player outside the Top 20 to reach the final here - the form book would suggest that number 19 is just around the corner; Sharapova has won her past 10 matches in straight sets, her past 44 against players outside the Top 20 and her past three against Jankovic.
 Serena Williams (USA #1) vs.  Agnieszka Radwanska (POL #4)
Head-to-head: Williams leads 4-0
Any suggestions that Serena Williams was a step off the pace after her struggles earlier in the tournament were dismissed in impressive fashion on Tuesday afternoon. Williams, a five-time champion, displayed her class in the first set and her battling qualities in the second to defuse the dangerous Li Na in swirling conditions out on Stadium court.
Like Williams, Radwanska's passage through to the semifinals has been far from plain sailing. Having dropped sets against both Magdalena Rybarikova and Sloane Stephens, the Pole came within two games of defeat in the last round against Kirsten Flipkens. Radwanska can ill afford any such slip-ups against Williams, who has dropped just one set in their four previous meetings and has won 19 of her last 20 matches against Top 5 ranked players.