INDIAN WELLS, CA, USA – The BNP Paribas Open draw has been shaved down to 16, and on a blockbuster Tuesday at the Indian Wells Tennis Garden, the quarterfinals will be set. Here’s a look at the match-ups.

Tuesday, Fourth Round

[1] Serena Williams (USA #1) vs. Kateryna Bondarenko (UKR #70)
Head-to-head: Williams leads 2-0
Key Stat: Williams’ last loss to a player outside the Top 50 was in 2014 (Charleston, Cepelova).
World No.1 Serena Wiliams showed signs of nerves and rust early in her third round match with Yulia Putintseva, but by the time it was over she looked like a player who was dead set on winning this title for the first time in 15 years. Still, Williams would like to rid herself of the slow starts that have created problems for her over the last few years. “I know last year I had a lot of slow starts, but I feel like I have done better this year,” Williams told the media on Sunday. “I had a slow start in this one, too, but it’s getting better. It just goes to show there is always something I can improve on. I’m always looking to improve on things.” On Tuesday she’ll look to improve her career record at Indian Wells to 21-1 when she meets qualifier Kateryna Bondarenko. The Ukranian reached the round of 16 for the first time at Indian Wells by surviving a third set tie-break with Lesia Tsurenko. Williams has won their two previous meetings, both in straight sets.

Pick: Williams in two

[3] Agnieszka Radwanska (POL #3) vs. [19] Jelena Jankovic (SRB #20)
Head-to-head: Radwanska leads, 6-3
Key Stat: Jankovic is bidding for her 50th Top 10 win today.
In a year that has been characterized by its unpredictability on the WTA Tour, Agnieszka Radwanska has been one of the steadier performers, making at least the semifinals in all three events she has played. Will she make it four in a row? Radwanska certainly owns the upper hand in her head-to-head with 2010 BNP Paribas Open champion Jelena Jankovic. The Serb took their first two meetings but since then Radwanska has won six of seven. The 2014 runner-up eased past Monica Niculescu in straight sets on Sunday and told reporters she’s yearning for the BNP Paribas Open title after the match. “Of course I was here in the final and really close to hold the trophy,” Radwanska said. “So this is another year to try. Obviously I am really trying every year to get the title. I really want to have that trophy at my home.” To reach the quarterfinals, Radwanska will have to maintain the hot hand against a hot opponent. San Diego resident and self-proclaimed California girl Jankovic comes in on a roll, having dropped just five games in her two rounds thus far.

Pick: Jankovic in three

[5] Simona Halep (ROU #5) vs. Barbora Strycova (CZE #37)
Head-to-head: Tied, 1-1 (Halep leads 1-0 at Tour-level)
Key Stat: Not since 1991 (Navratilova) has a WTA player successfully defended the Indian Wells title.
Though Serena Williams is the prohibitive favor in any WTA draw she enters, last year’s champion Simona Halep believes that the BNP Paribas Open is up for grabs. “I think the tournament is open and anyone can win it,” she told reporters at a media roundtable before the event started. “Many players are playing well now and young players are coming that are playing well.” The Romanian’s title defense has been going swimmingly thus far. After blitzing Vania King in her first match, she rolled past a world-class opponent in difficult conditions on Sunday night, braving the wind and the powerful game of Ekaterina Makarova to earn a straight-sets win. Halep’s opponent in the round of 16 has been playing good tennis herself. Barbora Strycova stunned Garbiñe Muguruza at the Australian Open to reach the second week, and last month she went all the way to the Dubai final before falling to Sara Errani. Is the 29-year-old Czech in good enough form to derail an in-form Halep? She certainly has the game, and the experience, to do it.

Pick: Halep in three

[8] Petra Kvitova (CZE #9) vs. [WC] Nicole Gibbs (USA #95)
Head-to-head: Kvitova leads 2-0
Key Stat: Gibbs has never won a set from a Top 10 player.
Petra Kvitova is still trying to find her form in the California desert. Meanwhile, a rising American qualifier is hitting her stride right before our eyes. Nicole Gibbs notched her career-best win against Madison Keys in the second round here, and will be looking to take down a bigger fish in two-time major champion Kvitova. But Gibbs knows she’s got her work cut out for her. “I have played her a couple times before also on some big stages: center court at New Haven and at US Open,” Gibbs told media after her straight-sets win over Yaroslava Shvedova on Sunday. “But I do feel like I’ve gotten to see what her level is like. Both matches have definitely been in her favor but competitive, so I’m just looking to hopefully get a bead on her serving early in the match.” Kvitova, who is hoping to match her career best result at Indian Wells, knows of the challenges that Gibbs can present. “I think she’s a very good mover,” Kvitova said. “She can catch a lot of balls and put back everything. I will have to be ready 100 percent, and really have to fight again.”

Pick: Gibbs in three

-Chris Oddo, wtatennis.com contributor