Updated

By Martyn Herman

ISTANBUL (Reuters) - Caroline Wozniacki will top of the WTA rankings for the second consecutive year but that does not make her the best player in the world, according to former men's number one Mats Wilander.

The 21-year-old Dane failed to reach the semi-finals at the WTA Championships in Istanbul, continuing her poor record at the biggest events and Wilander believes Wimbledon champion Petra Kvitova is the natural heir to the throne.

"The ranking is the result of not necessarily being the best player in the world it's the result of being the most consistent player in the world," Swede Wilander, who is working at the season-ending championships for TV channel Eurosport, told Reuters in an interview at the Sinan Erdem Arena.

"That's what it reflects. She's certainly not the best player in the world at her best, but at her worst she's probably the best player in the world compared to the others.

"Her range is very narrow, very even. But is she playing to be the number one in the world, to win lots of matches and make a lot of money or is she playing to win grand slams. I guess you'll have to ask her that."

Wozniacki's lack of success at the grand slams where her CV shows just one final, at the U.S. Open in 2009, has raised many questions about her validity at the top.

Wilander, who won seven in his glittering career, questioned whether she has the mentality to triumph at the majors.

Wilander said the fact that Wozniacki can receive on-court coaching from father Piotr during regular Tour events but not in the grand slams was also a telling factor.

"To be honest, the mistake that she is doing is that she is getting different treatment on the WTA Tour than she does at the grand slams because of the on-court coaching," he said. "You have to look at the obvious reasons.

"I'm not in favor of it for her because she seems lost compared to when she's getting coached."

While Wilander said Wozniacki needed to get a "foot quicker" and put "5 mph" on her serve, he believes Kvitova, who is breathing down her neck in the rankings after reaching the WTA Championships final at her first attempt, already has the weapons to grab top spot and start racking up slams.

"Absolutely," Wilander said. "Kvitova is going to be inconsistent because of the way she plays but mentally she is very consistent. She always looks for a way out and looks to come forward and be aggressive, she is happy to go to the net and make her opponents miss.

"She is very natural in figuring out what she needs to do with her game. Unlike Caroline she's already proved she can raise her game to win a slam."

(Reporting by Martyn Herman)