Simona Halep said she was basking in the glory of her position atop of the world standings after she secured the year-end WTA No 1 spot for the second consecutive year, but is a doubt for the year-ending finals in Singapore due to a back injury.
The Romanian star, who won her first Grand Slam title at the French Open, also secured titles in Shenzhen and Montreal, leading the rankings for 40 weeks this year.
Halep, 27, cannot be caught until January at the earliest, by which time only nine other players will have been world No 1 for longer.
Amelie Mauresmo (39 weeks), Maria Sharapova (21 weeks) and Kim Clijsters (20 weeks) are among those who have been left in Halep's wake, who says her phenomenal success was the result of her daily hard work.
"I feel great. I feel very happy that I am on top two years in a row," Halep told a news conference at Moscow's Kremlin Cup.
"It has been an amazing year, the best year of my life in tennis. Winning a Grand Slam makes it very special and it is going to be forever in my heart.
"I was very focused on what I have to do on court, I was working hard every day, I was very motivated all the year, I did not let the time fly just without putting my work into the game.
"I never gave up, I tried every day to become better and better. These things all together help me to keep me for four-five years in the top five."
The world No 1 has since been forced to pull out of the Kremlin Cup after experiencing back problems which has put her participation in Singapore next week in doubt.
"I tried everything I could to be ready here as I really wanted to play," Halep said. "But unfortunately the back is still causing me pain and I don't want to take any unnecessary risks.
"While it's disappointing to withdraw, I know it's important to put my health first."
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