Among Serena Williams’ sparkling numbers is her record at the WTA Finals - 25-5.
That's precisely 23 more wins than the rest of her challengers in the Red Group. But a knee injury means Williams may not be at full tilt in Singapore. However, she’s not alone in facing question marks about her health - Ana Ivanovic and debutants Eugenie Bouchard and Simona Halep have all dealt with their own issues of late.
In the White Group, Maria Sharapova and Petra Kvitova must contend with Caroline Wozniacki and Agnieszka Radwanska.
Here’s a look at both groups, predictions in hand.
Serena Williams: Asia hasn’t been kind to Williams this year. First she retired against 2014 nemesis Alizé Cornet in Wuhan because of a viral illness, then the World No.1 was a walkover in Beijing in the quarterfinals with that knee injury.
Just how healthy is she, then? That’s the key question.
Helping Williams is that the tournament is indoors - there are thus no external impediments to that lethal serve. And in the six times she’s contested the year-end championships indoors, only once has Williams not made the final - in 2007 when she played one set prior to pulling out of the event with a knee problem.
Simona Halep: Halep has made a quantum leap in the rankings this year, climbing into the Top 10 and subsequently Top 5. But whether it’s physical fatigue, mental fatigue or a combination, the exertions appear to be taking a toll on the slender Romanian: her last three defeats have all been of the upset variety, with Halep a walkover herself against Ivanovic in Beijing.
That said, she’s downed both Ivanovic and Bouchard this season, which is sure to be a confidence booster.
Eugenie Bouchard: Yes, Eugenie Bouchard had just come off a semifinal showing at the Australian Open, but did anyone think that when the Canadian helped launch the Road To Singapore in January she’d be in the eight-woman field around nine months later?
Like Halep, Bouchard hasn’t been in top form of late, and similar to Halep, that’s probably down to a combination of physical and mental tiredness: in seven tournaments since her charge at Wimbledon, Bouchard has made one quarterfinal. However, Bouchard always loves to test herself against the elite, feeling she belongs in their company - and for a while to come.
Ana Ivanovic: Call it a tale of two seasons for Ivanovic. She underachieved - by her own admission - at Grand Slams but thrived away from the majors.
The Serb did, though, top Williams at the Australian Open, and that added to victories over the likes of Sharapova (on clay, too), Halep and Wozniacki this year. Ivanovic’s return to the WTA Finals after a six-year absence is a heart-warming tale, and by no means should she be discounted to go all the way - assuming, of course, that she’s fit following a lingering hip injury.
Predictions: 1: Williams, 2: Ivanovic, 3: Bouchard, 4: Halep
Maria Sharapova: It-s been 10 years since Sharapova won her lone year-end title - and four since she won an indoor tournament not on clay. And back in Memphis in 2010, Sharapova didn’t need to beat a Top 65 player on the way to the title.
Things are obviously tougher in Singapore. The Russian, though, presumably enters the competition in good spirits, having overcome Kvitova in the Beijing finale.
Further, here are some positive group stats for Sharapova: She's won five in a row versus Kvitova, owns a 10-2 record against the slumping Radwanska, and has won three of her last four against Wozniacki.
Petra Kvitova: The ups and downs of Kvitova. Not many thought she'd win Wimbledon, but we all know what happened at the All-England Club. It raised hopes of an extended stay at the US Open, but Kvitova crashed out to the energetic bundle of outsider Aleksandra Krunic.
Kvitova rebounded in Asia, toppling Bouchard once again in Wuhan, and made the final in Beijing - she was bettered by Sharapova in what was a rare loss in a final for the lefty. Competing indoors will be to Kvitova's liking, and she's one of three past winners in the field.
Agnieszka Radwanska: Of the eight players in Singapore, Radwanska figures to be the longest shot. Qualifying was largely thanks to a fine first half, and if the Pole hadn't won in Montréal in August, who knows if she’d have landed a berth. Her last four losses have come to players outside the Top 35.
Besides the poor record against Sharapova, Radwanska is 1-5 against Kvitova and fell in her lone tussle in 2014 against Wozniacki, one of her best pals. The outlook is gloomy.
Caroline Wozniacki: Deep into the European clay court swing, Wozniacki - as she pointed out - was well out of contention for a place in Singapore. But talk about a reversal of fortune. On her preferred surface of hard courts, the Dane has gone 25-7 since Wimbledon - with three of those losses inflicted by Williams, another of her good buddies.
Wozniacki, you’ll note, upended Sharapova in one of the most intense matches of 2014, so won’t be overawed facing the World No.2. That'll be one to especially watch. Sharapova, Kvitova and Wozniacki would seem to be, realistically, battling for the two semifinal slots - and no order would come as a surprise.
Predictions: 1. Sharapova, 2. Wozniacki, 3. Kvitova, 4. Radwanska
Semifinals: Williams d. Wozniacki, Ivanovic d. Sharapova
Final: Williams d. Ivanovic
~ Ravi Ubha (@raviubha) has written for ESPN.com, CNN.com, the New York Times and Wall Street Journal, and is also a tennis broadcaster. He is based in London.