Red, white and--who?

Was a fun night with the girls @ARadwanska @Simona_Halep. Now time for dinner and bed #wtafinals 💤 pic.twitter.com/khbqkcLCG2

— Petra Kvitova (@Petra_Kvitova) October 23, 2015

Friday's WTA Finals singles draw resulted in these two round robin groups:

RED GROUP
Simona Halep
Maria Sharapova
Agnieszka Radwanska
Flavia Pennetta

WHITE GROUP
Garbine Muguruza
Petra Kvitova
Angelique Kerber
Lucie Safarova

Here is the doubles draw:

RED GROUP
Martina Hingis/Sania Mirza
Timea Babos/Kristina Mladenovic
Raquel Kops-Jones/Abigail Spears
Andrea Hlavackova/Lucie Hradecka

WHITE GROUP
Bethanie Mattek-Sands/Lucie Safarova
Chan Hao-Ching/Chan Jung-Jan
Caroline Garcia/Katerina Srebotnik
Garbine Muguruza/Carla Suarez Navarro

Safarova and Muguruza  are doing double duty at the event, playing in both competitions.

Round robin singles play begins in Singapore on Sunday, when Halep and Pennetta hit the first white group balls. The Red Group is interesting in that Radwanska and Pennetta come in with some momentum. Radwanska's season was sub-par until she hit the Asian swing and won Tokoyo. Pennetta won the U.S. Open, is retiring from tennis at the end of the season, and--while I don't like the expression--"nothing to lose" kind of suits her.

Halep and Sharapova, on the other hand, have both been dealing with injury issues; also, Halep has had some problems closing big matches.

Somehow, right-hander Muguruza slipped into the White Group, which is filled with left-handed troublemakers. Kvitova, who has won the event before, will get an automatic boost by playing on an indoor court. Her countrywoman, Safarova, has been recovering from serious illness and expectations regarding her performance are lower than they would have been earlier in the season.

Kerber is always unprdictable, but has had such a good season that she shouldn't be counted out. Muguruza has everyone's attention; the fact that she's in the final eight says it all.

The WTA Finals can never be predicted, however. We're always surprised that "(fill in the blank) lost all 3 of her round rubber matches." Players are tired, players are dealing with a season's worth of injury and rehab, and--to make the question mark bigger this year--world number 1 Serena Williams won't be there.

Of note:

Pennetta has winning records over both Halep and Sharapova.

Kvitova and Muguruza have never before played one another.

In seven tries, Safarova has never beaten Kvitova.

Radwanska and Sharapova have played each other 12 times, and Radwanska has won only two of those matches.

Three of the players--Pennetta, Muguruza and Safarova--are making their WTA Finals debuts.

The Red Group has already distinguished itself: All the players wore black for the draw ceremony, except for Sharapova and Pennetta, who wore black-white combo dresses. A sign of things to come?