UPDATE 3-Tennis-Safina stages comeback to reach Stuttgart final

* World number one Safina beats Pennetta to reach final

* Kuznetsova downs Dementieva in first semi-final

(updates with details)

STUTTGART, Germany, May 2 (Reuters) - World number one Dinara Safina staged a comeback to beat Italian Flavia Pennetta 3-6 7-5 6-0 on Saturday and reach the Stuttgart Grand Prix final where she will face fellow Russian Svetlana Kuznetsova.

Pennetta had punished the Australian Open runner-up with some powerful groundstrokes on the indoor clay court as the Russian struggled with her serve, hitting five double faults in the first set which the Italian won after 35 minutes.

Safina, who topped the rankings on April 20, was broken again as world number 14 Pennetta looked to be cruising to victory with a 3-1 lead.

But the Italian then lost three consecutive games to allow the Russian, who had not dropped a set and had only lost 13 games in her previous three rounds, to level at 5-5.

Safina never looked back, winning eight straight games as her 27-year-old opponent collapsed in the third, to reach her third final after Sydney and Melbourne.

"I was a bit slow starting today," Safina said. "I did not play my best tennis, but I did enough to get through. It was smart to call on my coach, he was pretty angry with me and I changed my game completely after that."