Caroline Wozniacki battled back from a set down to defeat Francesca Schiavone of Italy 3-6, 6-1, 6-1 at the WTA Championships here yesterday, a win that ensures she will end the year as the world's No 1 player.
Also in the Maroon Group, Australian Samantha Stosur lost 4-6, 6-4, 7-6 to Russian Elena Dementieva but by winning the first set booked her place in the last four alongside Wozniacki.
Belgium's Kim Clijsters beat Victoria Azarenka of Belarus 6-4, 5-7, 6-1, to advance to the semi-finals from the White Group along with Vera Zvonareva.
Wozniacki needed two wins at the $4.55m tournament in the Qatari capital to ensure she could not be caught at the top of the rankings by Zvonareva.
After blowing away Dementieva in her group opener, the Dane suffered a shock defeat to Stosur on Wednesday to give Zvonareva hope. However, the 20-year-old made no mistake against Schiavone.
"Francesca was playing really good in the first set and I didn't have too many chances to break her," said Wozniacki.
"I just hung in there and kept my focus, tried to get a little more aggressive and not let her dictate the game in the second and third."
Wozniacki was delighted to finish the year as the world's top player.
"That's something I've dreamed about since I was a little girl," she said. "I'm really happy and proud of what I've achieved this year."
Schiavone came out firing on all cylinders and caught Wozniacki off guard, to take the opening set, before the Dane found her range.