Tuesday, Second Round
 Serena Williams (USA #1) vs. Laura Robson (GBR #39)
Head-to-head: first meeting
Laura Robson showed before Monday that she does not fear WTA stars, having beaten Kim Clijsters, Li Na, Petra Kvitova and Agnieszka Radwanska previously. She showed that lack of intimidation again in her Madrid opener by surrendering just five games against seven-time Grand Slam champion Venus Williams. While Robson has won three of her last four matches against Top 10 opponents, she has never faced a World No.1 and certainly not one likely out to avenge her sister's defeat.
Serena Williams was denied a chance for a 25th meeting with Venus, and surely will be looking to show rising star Robson who is the WTA's most dominant player these days. She is fresh off her 50th WTA title in Madrid, which was her fourth of the season and the seventh of her career on clay. It also put to rest any question about her productivity on red clay, as before last week she had not been to a red clay final since winning Roland Garros in 2002 - which was a couple of weeks after she won her lone Rome title. Robson could hold out hope in knowing that two of Williams' six losses since the start of 2012 came at the hands of lefties - Ekaterina Makarova at the Australian Open in 2012 and Angelique Kerber at Cincinnati in 2012.
 Agnieszka Radwanska (POL #4) vs. [Q] Simona Halep (ROU #64)
Head-to-head: Radwanska leads 3-0
After winning her first 13 matches of 2013, it has been an up-and-down campaign for Agnieszka Radwanska since, and she will be looking to avoid losing her opener in Rome for the third straight year.
Though she has yet to go beyond the third round of an event this year, Simona Halep was dominant in her opener against Svetlana Kuznetsova on Monday - giving up just two games. She is certainly at her most dangerous on the dirt, with her WTA clay court résumé highlighted by three runner-up showings and one semifinal appearance. However, she has never mustered a set against Radwanska, including on clay in the final of Brussels last year. If she is able to pull off the upset, it would be her second Top 10 win and her best one in terms of ranking, surpassing her victory over then-No.6 Li Na at the 2011 US Open.
 Sloane Stephens (USA #17) vs. [WC] Flavia Pennetta (ITA #104)
Head-to-head: Pennetta leads 2-0
Though Sloane Stephens is the on-paper favorite, a victory for Flavia Pennetta would not be a huge shock for several reasons. Her seven WTA titles on clay is tied for third-most among active players. In her two previous meetings with Stephens, both of which came on clay and one of which came here last year, she dropped a combined seven games. Also, since Stephens made her thrilling run to the semifinals of the Australian Open, she is 2-7 and in the midst of a four-match losing streak. Regardless, she is still the second-highest-ranked American and will be looking to turn her 2013 clay season around with her first win on the dirt.
Pennetta is in the midst of her own struggles. She has not recorded a Top 20 win since her defeat of then-No.16 Maria Kirilenko in the first round here last year en route to the quarterfinals. And in fact, she has not made a quarterfinal since as she has dealt with a variety of injuries. Nevertheless, her previous success on clay and experience should not be overlooked.
Around the grounds...
No.13 seed Roberta Vinci looks for just her second win in six meetings with Elena Vesnina, Petra Kvitova and Sabine Lisicki square off, and Caroline Wozniacki and Ana Ivanovic get their Rome campaigns started.