(Updates after men's final)
MOSCOW Oct 14 (Reuters) - Russia's Elena Dementieva gave herself an early birthday present when she rallied after dropping the first set to beat Serena Williams 5-7 6-1 6-1 and win her maiden Kremlin Cup title on Sunday.
Top seed Nikolay Davydenko prevailed over France's Paul-Henri Mathieu 7-5 7-6 in the men's final later in the day to retain his Kremlin Cup crown and complete the Russian double at the $2.3 million indoor tournament.
World number four Davydenko, who called for a medical timeout late in the second set to treat his right wrist, needed four match points to finish off the fourth-seeded Frenchman for his third victory in Moscow in the last four years.
Dementieva, who turns 26 on Monday, came out storming after losing the first set, breaking the fourth-seeded American three times in each of the next two sets to claim her first career win over the former world number one in emphatic fashion.
The 14th-ranked Russian had not even won a set off Williams in their four previous meetings.
Both players traded breaks several times in the first set before Williams broke to love in the 12th game to take a one-set lead.
The Muscovite, seeking her first title on home soil in her 11th Kremlin Cup appearance and after losing her two previous finals here in 2001 and 2004, came out fighting in the second set.
Urged on by a near capacity 10,000-strong home crowd, she broke the world number seven three times to claim the second set in just 24 minutes before repeating the feat in the decider.
Serving for the match, Dementieva was able to overcome her nerves to clinch a breakthrough victory and the $182,000 first prize on her second opportunity when Williams's forehand sailed wide.
"It's just a great victory for me," the Russian told reporters after winning her eighth career title.
"This has been one of my favourite tournaments and playing at home in front of my fans, finally I was able to do it. It is a very important win for me and my whole career."
"She just played really unbelievable, she should play like that more often," said Williams, who was making her second visit to Moscow 10 years after her debut when she lost in the first round as a 16-year-old.
"I'm not going to make excuses for myself. I played terrible. I had a feeling that almost every shot I hit, it was out," added the Australian Open champion, who committed 59 unforced errors to her opponent's 31.