SINGAPORE - The group phase is in the books and the knockout round is set for a thrilling weekend at the BNP Paribas WTA Finals Singapore presented by SC Global. Much like during the regular season, Caroline Garcia topped the Red Group with a last-minute surge past fellow qualifier Caroline Wozniacki, and Karolina Pliskova has her No.1 destiny in her own hands as she plays her first semifinal at the year-end event, with Venus Williams joining her out of the White Group. 

Saturday's semifinals will see the battle of the two best servers in the tournament, with Pliskova taking on Wozniacki (more on that below), followed by two of the most remarkable stories of the season, in Venus vs. Garcia. 

But before we turn the page on the round robin stage, here's a look back on the biggest takeaways from the first six days of the Finals.

Caroline Wozniacki is serving lights out. 

She may have been nipped in the end by Caroline Garcia in the final group match, failing to serve it out at 5-3 in the third to lose 0-6, 6-3, 7-5, but Wozniacki's serve has been a revelation in Singapore. In fact, Saturday's semifinal between Wozniacki and Pliskova will feature the two best statistical servers in the tournament, with Wozniacki actually leading in nearly all the key categories, ahead of Pliskova, who is underperforming compared to her season averages.

Aces:
Wozniacki: 12 aces, averaging 4 per match. Season average: 2.6 per match.
Pliskova: 10 aces, averaging 3.3 per match. Season average: 6.6 per match.

First serve points won:
Wozniacki: 69.6%. Season average 64.3% (+5.3%)
Pliskova: 67.3%. Season average 73.3% (-6.0%)

Service points won:
Wozniacki: 62.8%. Season average 59.4% (+3.4%)
Pliskova: 60.5%. Season average 62.9% (-1.4%)

Service games won:
Wozniacki: 82.1%. Season average 72.4% (+9.7%)
Pliskova: 70.8%. Season average 79.5% (-8.7%)

So how will it all net out on Saturday? Her serving did tail off as Garcia was able to put more pressure on return in the final two sets of their match. 

Caroline Garcia is Ms. October.

Baseball may have had Mr. October, but this year's WTA has Ms. October, in the spectacular rise of Garcia. The 24-year-old has been the comeback kid throughout the month, having mounted comebacks in four key matches to win her group in her tournament debut. Ashleigh Barty served for the title in Wuhan, Elina Svitolina served for the quarterfinals in Beijing and in the second match in Singapore, and Wozniacki served for the win on Friday. Garcia ended up winning them all. 

"Sometimes when you are down, you play a little bit more relaxed. I don't know. I don't feel more relaxed, but maybe."

- Caroline Garcia

"I can't explain it perfectly," Garcia said when asked about her comeback prowess. "I know that recently, like in the past few weeks, I have improved my rhythm. On the last game, I know that the other one is going to get a little bit tight, but I'm still very careful to try to bring every ball in I can, be aggressive like I'm used to doing.

And sometimes when you are down, you maybe play a little bit more relaxed. I don't know. I don't feel more relaxed, but maybe. So I just try to keep fighting, keep learning about this experience to be down and come back. I mean, I turn things around."

Venus Williams is here to win. 

At 37-years-old, you don't make the long flight to Singapore for a sight-seeing vacation. Venus has been on a mission this week. Playing in her first WTA Finals since 2009, the American has dug in to battle not only her opponents but the surface. After her straight-set loss to Pliskova in the opening match, her sole critique was that she missed too much. Since then, she has battled past two big hitters in Jelena Ostapenko and Garbiñe Muguruza, reigning in her power, playing smart tactically, and forcing the hitters to hit through her. 

Venus is the only player in the field without a title this season, yet she is also the only one remaining who made not just one but two major finals this year. Now into the knockout phase, she has a great chance to put the perfect code on a remarkable season.

Simona Halep comes up short in the round robin stage again.

In her tournament debut in 2014, Halep defeated Serena Williams in group play and went on to make the championship match at the WTA Finals. Since then, the Romanian has struck out when it comes to must-win matches in the round-robin format. In the last three years she has not won a set, losing to Agnieszka Radwanska in 2015, Dominika Cibulkova in 2016, and Svitolina on Friday. 

"I just talked to my coach before the match that this system, I don't like," Halep said with a wry smile. "You stay, like, in the stress all week. Even if you lose, of course, you have another chance, but I just want to be, like, you lose, you go home. You know something, yes or no.

"But it's good for some players that are losing the first match. They have another chance. So I always win the first one and then I lose. So is not a good thing for me. But maybe I can improve the next years."

The slower court surface in Singapore also has the tendency to get into players' heads, and though Halep is a counter-puncher, she typically needs a slightly faster court to get the most out of her game. 

"Today I just felt 100% that the court is not for me and I cannot finish a point. It's not going. So it was a little bit tough to find the rhythm and also to make a winner. Of course, my game is not making winners all the time but a little bit more. So my feeling is that I fought. I fought till the end. It was a good match. Not great, but was good match."

Halep was in good spirits after the loss, seemingly relieved more than anything that her season was finally over and she could relax. It's an understandable reaction after her season, which started with disappointment after a knee injury, only to hit a consistently high level from Stuttgart through the rest of the season. The opportunity to finish the season at No.1 (see below) also softened the blow.

Chase for Year-End No.1 comes down to Halep or Pliskova:

At the start of the tournament, seven women had a chance to finish the season at No.1. After six days of group play, that field now comes down to No.1 Simona Halep and No.3 Karolina Pliskova. 

The scenario is simple: Karolina Pliskova must win the Singapore title to overtake Halep and finish the year at No.1. If she does not win the trophy, Halep will finish the year at No.1.

There have been just 12 women to hold the prestigious year-end No.1 ranking since the computerized rankings were introduced in 1975:

Chris Evert: 1975, 1976, 1977, 1980, 1981
Martina Navratilova: 1978, 1979, 1982, 1983, 1984, 1985, 1986
Stefanie Graf: 1987, 1988, 1989, 1990, 1993, 1994, 1995 (shared with Seles), 1996
Monica Seles: 1991, 1992, 1995 (shared with Graf)
Martina Hingis: 1997, 1999, 2000
Lindsay Davenport: 1998, 2001, 2004, 2005
Serena Williams: 2002, 2009, 2013, 2014, 2015
Justine Henin: 2003, 2006, 2007
Jelena Jankovic: 2008
Caroline Wozniacki: 2010, 2011
Victoria Azarenka: 2012
Angelique Kerber: 2016

GIF of the Day: Trophy pose, Caroline Garcia. 

Shot of the Day: Caroline Wozniacki's pitch-perfect lob. 

Quote of the Day: Well at least Elina Svitolina can laugh about it now.

Q. Obviously we don't know what's going to happen, but if you get through, would you take Svitolina out to go shopping in the mall?
CAROLINE GARCIA: I mean, I guess she probably a little bit pissed about me for the last match, so I don't know (smiling). But I mean, I can always ask her out for a drink or something.
...
Q. Talking of scenarios, your win has put Garcia at the top of the group. So we asked her is she going to take you out for a drink or a meal to say thank you.
ELINA SVITOLINA: Yeah, I think I'm expecting more than a drink. Sorry (smiling). Because we also played in Beijing, and she worked really hard for it, but still, you know, I'm waiting (smiling).