MIAMI, FL, USA - A loaded day of action at the Sony Open Tennis will see all eight fourth round matches played, including those involving Maria Sharapova and Serena Williams - each of whom is coming off a third round battle.
Monday, Fourth Round
 Maria Sharapova (RUS #7) vs.  Kirsten Flipkens (BEL #23)
Head-to-head: Sharapova leads 4-0
Though Maria Sharapova is the clear favorite in her fourth round tilt with Kirsten Flipkens, fatigue could make the winner not an obvious choice. Sharapova needed nine match points in her almost three hour third round victory over Lucie Safarova on Saturday. And Flipkens should come into this match awfully fresh, as she has only taken the court for her second round defeat of Virginie Razzano, having received a first round bye and a third round walkover.
Sharapova has yet to drop a set in their series and only surrendered five games combined in their last two meetings. If Flipkens is able to pull off the upset, it would be the Belgian's fourth Top 10 win and the second-best win of her career - with her triumph over No.5 Samantha Stosur at 's-Hertogenbosch in 2012 her best.
 Serena Williams (USA #1) vs. [Q] Coco Vandeweghe (USA #104)
Head-to-head: Williams leads 2-0
Serena Williams and fellow American Coco Vandeweghe are both coming off third round battles that lasted about two and a half hours, Williams having beaten Caroline Garcia and Vandeweghe edging Stosur in a match that ended at about 2:30am Sunday.
It has been a magical run for Vandeweghe, who had never won a main draw match here previously, but has won two qualifying matches and three main draw ones so far this fortnight. Interestingly enough, the last time she won three straight WTA main draw matches, it was en route to her lone WTA final at Stanford in 2012, and her conqueror in that final was none other than Williams. This will be Vandeweghe's first clash against a reigning World No.1 and if she can pull off the upset of the six-time Miami champion, it will be her first Top 5 win.
 Petra Kvitova (CZE #8) vs.  Ana Ivanovic (SRB #13)
Head-to-head: Ivanovic leads 4-2
Ana Ivanovic has quietly cruised through the draw so far in Miami, dropping just two games against Lauren Davis in the second round and recording another comfortable straight set victory over newly crowned Indian Wells champion Flavia Pennetta in the third round. That improved her to 14-4 on the season and left her a win away from matching her best outing here - a quarterfinal showing at her Miami debut in 2005.
Standing in the Serb's way is fellow former Grand Slam winner Petra Kvitova, who is into the fourth round here for the first time in seven outings. Their series has been back-and-forth, with Ivanovic winning the first three encounters and Kvitova two of the last three.
Also on court...
Three-time Miami champion Venus Williams looks to become the 10th player with 650 pro match wins when she takes on Dominika Cibulkova, and Li Na, Agnieszka Radwanska, Angelique Kerber and Caroline Wozniacki also will be aiming for quarterfinal berths.
Find the listings for Monday's play on the WTA TV developed by Xerox.