Sunday's draw appeared to hand the advantage to Dinara Safina, 23, as she was placed in the easier of the two four-women groups that will be contested at the Khalifa Tennis Centre on the shores of the Persian Gulf.
She will face late qualifier Jelena Jankovic, of Serbia, and tournament debutants Caroline Wozniacki, the US Open runner-up from Denmark, and Victoria Azarenka, of Belarus, in the White Group.
Serena, who claimed the number one spot from Safina at the China Open earlier this month, once again found herself a handful of points behind the Russian when the latest world rankings were published by the WTA yesterday.
The American is also in the much tougher Maroon Group in Doha where she must play sister Venus, the defending champion, and formidable Russians Svetlana Kuznetsova, the French Open winner, and Olympic gold medallist Elena Dementieva.
To have the battle for No.1 going to the wire is a dream scenario for women's tour chiefs and the Qatari tennis authorities who paid $42 million to stage the season-ending event for three years until it moves to Istanbul in 2011.
"We always wish for the number one ranking to be on the line at the tour finals and that's what we've got this year," Andrew Walker, the WTA's senior vice-president of marketing and communications told Reuters by telephone.
"This tournament is the crown jewel for the Tour and we have an incredible line-up this year, there's certainly no weak links in there. We've got the marquee names and the next generation of stars. There are some great rivalries in the making."
The WTA Tour finals have often struggled to capture the imagination of the public.
Last year in Doha the early round robin matches were played in a muted atmosphere, although the fact that Serbia's Jankovic had already clinched the number one spot hardly boosted late ticket sales.
This time, however, everything will be on the line when the $4.5 million tournament gets under way today.
Naked cover-girl
Eleven times grand slam champion Serena arrives a whisker behind despite winning the Australian Open and Wimbledon, though it is her reputation as much as what she feels is her rightful place at the top of the rankings she is desperate to restore.
The American, who recently posed naked for a magazine cover, faces a ban or large fine when the International Tennis Federation (ITF) disciplinary committee meets next month to discuss her foul-mouthed outburst at the US Open.
While her appearances in Doha are sure to create an extra buzz, she will be happy to let her tennis do the talking.
Serena made little attempt to disguise her annoyance that Safina, who has never won a grand slam title, led the rankings for 25 consecutive weeks this year and few would argue that her best is still too good for pretty much everybody.
To confirm her superiority, however, she will have to go further in Doha than Safina who holds a 155-point lead.
If both players go out at the same stage the number one ranking will probably be decided by who wins most round-robin matches which are each worth 160 ranking points.
Safina, who briefly lost the world number one ranking in Beijing only to grab it back just in time for Doha due to a quirk of the rankings system, has struggled to win over the critics who say she does not deserve top spot.
The Russian will be determined to do better than last year in Doha when she failed to win a match.