SINGAPORE - The White Group will take center stage on Day 4 in Singapore, and there’s lots to be sorted out when they do. Garbine Muguruza has a semifinal qualification within her sights, and Czech mates Petra Kvitova and Lucie Safarova will clash with each searching for their first win at this year’s WTA Finals Singapore Presented by SC Global. Here’s a breakdown of what’s on tap.
 Petra Kvitova (CZE # 5) vs.  Lucie Safarova (CZE #9)
Head-to-head: Kvitova leads, 7-0
Key Stat: Safarova has taken Kvitova to three sets in their last three meetings.
Seven meetings, seven losses. What will it take for Lucie Safarova to finally get over the hump against her friend and Fed Cup teammate Petra Kvitova? It all starts with breaking the vaunted Kvitova serve. Safarova couldn’t do it once in their last meeting in New Haven, but she knows she’ll need to find a way on Wednesday at Singapore Stadium in order to take the pressure off her own delivery. ''She's a big hitter, so she is putting a lot of pressure on you serving really big,'' said Safarova, after falling to Kvitova in this year’s New Haven final. ''It's kind of hard to break into her serve, and it puts extra pressure on your serve.”
If there was ever a time for Safarova to defeat Kvitova, this could be it. Petra struggled in her Singapore opener, falling to Angelique Kerber in straight sets while tossing in 44 unforced errors in a listless effort. 2015 has been a long grind for Kvitova. She has struggled with the after-effects of a bout with mononucleosis, and appears to be stumbling down the stretch, having now lost four of five matches since September.
But one mustn’t overlook Kvitova’s championship pedigree and competitive fire. She’s found a way to summon her best despite difficult circumstances on many occasions in 2015. Many expected her summer to be a wash when she suddenly rebounded from first-round exits in Toronto and Cincinnati to win the New Haven title and produce a career-best U.S. Open performance.
Will Petra have the fire on Wednesday, or is it finally Safarova’s time to shine?
Pick: Safarova in three
 Garbine Muguruza (ESP #3) vs.  Angelique Kerber (GER #7)
Head-to-head: Tied, 3-3
Key Stat: Both Muguruza and Kerber can qualify for the semifinals with a win today, depending on the result of the Safarova-Kvitova match.
22-year-old Garbine Muguruza dazzled in her WTA Finals debut, scorching winners and exhibiting the body language of a champion who has been there and done that in her 6-3, 7-6(4) win over Lucie Safarova. It’s a credit to the maturity of the youngest player in this year’s field that she has come out firing in Singapore, unintimidated by the elite field and the pressure to prove that her run to the Wimbledon final was no fluke.
On Wednesday the bold-striking Spaniard will look to keep proving herself against a familiar opponent in Angelique Kerber. Muguruza has enjoyed success against the German in 2015, snapping a three-match losing streak against her with wins at Roland Garros, Wimbledon and Wuhan, but the determined Kerber will no doubt be seeking her revenge with a spot in the semifinals on the line.
Kerber, currently tied atop the WTA leaderboard with 53 wins in 2015, sparkled in her victory over Petra Kvitova on Monday, snapping a four-match losing streak against the Czech. With four titles under her belt in 2015, her confidence is certainly where it needs to be, but getting past the high-octane ground game of Muguruza is proving to be an increasingly difficult challenge for all comers.
Faced with the Spaniard’s daunting power, Kerber will certainly need to hit her spots on serve and find ways to keep Muguruza on the run. Counterpunching is Kerber’s forte, but counterpunching alone will not be enough to defuse the bristling power that she’ll face against Muguruza.
Pick: Muguruza in two tight sets
Also on Tap: Hingis and Mirza seeking semifinal qualification in Red Group doubles.
Key Stat: Hingis and Mirza have dropped two sets in 18 consecutive wins prior to today’s action.
Can anybody stop the dynamic duo of Martina Hingis and Sania Mirza in Singapore? Since falling to the Chan sisters in Cincinnati, the pairing have reeled off 18 consecutive wins (titles at the US Open, Guangzhou, Wuhan and Beijing), including their straight-sets takedown of Raquel Kops-Jones and Abigail Spears on Monday.
Up next for Hingis and Mirza is the Czech duo of Andrea Hlavackova and Lucie Hradecka, the 2012 WTA Finals runner-ups. In the other doubles tilt, Kops-Jones and Spears will face Timea Babos and Kristina Mladenovic.