Wozniacki has enjoyed a fine season having reached seven finals but she has the chance to claim the biggest title of her career after a 7-6 6-3 victory over Karolina Pliskova on Saturday in the opening semi-final.
The Dane lost in the final of this even in Doha in 2010 and has also suffered defeat in two US Open finals but she continued her week in Singapore with a dominant display to end Pliskova's season and year-end no 1 dream.
With Halep already knocked out of the tournament, Pliskova was the only player who could prevent the Romanian ending the year at the top of the rankings but having lost her final group game she folded again against Wozniacki.
The Danish sixth seed claimed an epic first set tie break by 11-9 before getting the better of a second set that featured five breaks of serve to eventually close out the match with a 7-6 6-3 victory.
"That was a little bit crazy. It was a rollercoaster," said Wozniacki.
"I'm just happy I got that first set under my belt. I've been playing really great tennis this week so to be in the finals, it means a lot to me."
Standing in Wozniacki's way will be 37-year-old Venus Williams who also has the chance to put a host of near misses this season behind her.
The older of the Williams sisters is without a title in 2017 but has enjoyed a fine year despite losing in the final of both Wimbledon and the Australian Open as well as reaching the last four at the US Open.
She battled back from losing a first set tie-break against Caroline Garcia to reach a third year-end final of her career and in doing so become the oldest ever woman to do so.
Williams beats the benchmark set by Martina Navratilova who reached the final aged 36 in 1992 and will now take on Wozniacki for a second WTA Finals title having won it nine years ago in 2008.
"It's hard to produce your best tennis at the end of the year because you've given so much but it's so important to do that in this tournament," Williams said.
"It's amazing to almost be standing in the winner's circle. It's not over till the fat lady sings and I'm not fat. I watch my figure."
Garcia was the form player coming into the event having won back-to-back titles in China to claim the final spot and looked on course to continue the journey when she bossed the first set tie-break.
But Williams hit back brilliantly to claim her place in the final with a 6-7 6-2 6-3 success and remain on course for a landmark title.