Caroline Wozniacki secured the year-end number one spot in the world ranking on Thursday, becoming the first ever Dane to do so, but only after suffering an early fright at the WTA Tour Championships here.
For an hour, the 20-year-old top seed seemed in danger of going out of the event, until she worked out the clever tactical patterns of Francesca Schiavone, the French Open champion from Italy, and triumphed 3-6, 6-1, 6-1.
Not until midway through the second set did that happen as Wozniacki swapped containment for going on the offensive against Schiavone, who mixed topspin with slice, slow-balling with pace, and net attacks with base-lining, all with equal facility.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Twice Wozniacki's father-coach Piotr came to the courtside, where he knelt before his daughter to offer unusually animated advice.
It seemed to help, although the fourth and the fifth games of the third set were also fiercely contested and pivotal in preventing a Schiavone comeback.
"This is something I have dreamed about since I was a little girl," said Wozniacki, who will become the youngest year-end number one since Martina Hingis in 2000.
"I am really happy and proud about what I have achieved this year."
Wozniacki joined Australia's Samantha Stosur as a semi-finals qualifier from the maroon group at the expense of Elena Dementieva, the Olympic champion from Russia, who will be out even if she beats Schiavone on Friday.
Asked what she might splash out on to celebrate her new status, Wozniacki said: "When I do well I like to buy a small present for myself. I usually like handbags or sunglasses -- they make good accessories -- but I might buy presents for all the people around me."
With her round robin wins here, the Dane has done enough to prevent Vera Zvonareva, the Russian world number two, from overtaking her in the ranking.
Schiavone chiselled a break of serve in the fourth game and, Wozniacki, who unexpectedly lost the night before to Stosur, suddenly began to look anxious.
But a turning point came with a controversy in the fourth game of the second set, when Wozniacki appealed to the Hawkeye computerised replay system.
To the surprise of many she got an 'out' call on her backhand cross-court reversed -- only for Schiavone to make her own, very animated appeal.
The Italian complained that the line judge's call had denied her a chance of trying to return the ball, but the umpire disagreed.
That annoyed Schiavone, firing her up to cling on to her service game for 1-3 after a long tussle. There immediately followed another lengthy struggle in which Wozniacki was made to survive two deuces before holding serve and reaching 4-1 for a stranglehold on the second set.
In the third, the Dane saved a break back point for 2-2 and followed it by winning the rally of the match, sprinting three times behind the baseline to retrieve the ball and then wowing the crowd with a counter-attacking cross-court angled drive.
"It was really difficult," admitted Wozniacki. "I just had to hang on and keep my focus, and then be a little bit more aggressive."
Earlier, Dementieva beat Stosur, the world number five, 4-6, 6-4, 7-6 (7/4), but by taking the opening set the Aussie did enough to secure her passage.
