The 17-year-old came from a set down to clinch her second WTA title in two months with a 3-6 7-6 7-5 victory.

Kuznetsova, who won the Helsinki Open in August as a qualifier, was the ITF's Junior Player of the Year last season.

Her victory means she will break into the world's top 50 next week after being ranked 264 at the beginning of the year.

"The match was very, very tough for me mentally. It was a different situation to Helsinki when I won my first WTA title," she said.

"I wasn't nervous there at all. But here it was very difficult because having to beat Arantxa (Sanchez-Vicario) yesterday was the most difficult day of my life, and so I felt obligated to win today."

Dramatic decider

Eighth seed Martinez claimed the opening set of the 163-minute marathon by breaking to lead 5-3, and then holding off a break point in the next game.

Kuznetsova dropped her serve to lose the first game of the second set but levelled at 2-2, when Martinez netted a weak backhand, and went on to win a tie-break.

In a dramatic final set, Kuznetsova broke to take a 4-3 lead but failed to serve out the match at 5-4.

She then held four match points before Martinez eventually levelled with her third break point.

But Martinez then dropped her serve again after leading 40-0 and Kuznetsova did not waste her second chance.