Kirilenko, 18, from Moscow, improved to 36-21 this season after the breakthrough.

Groenefeld, 20, proved to be a tough competitor, throwing down six aces to only one for the winner. Kirilenko also had a few nervous moments as she converted on only five of her 16 break points.

Kirilenko, ranked 45th in the world, missed a chance to serve out the match in the ninth game of the second set, dropping serve after saving three break points.

But she recovered in dramatic fashion to break world number 30 Groenefeld a game later and claim victory. 'I'm so happy to have won - I still can't believe it. This is an important breakthrough for me,' said Kirilenko.

'The first four games were very difficult, but after that I settled down. Then in the second set I played very well. When I served for the match, I tried to think of it as just another game, but I didn't serve well. Fortunately, I was able to get the break back straight away.'

She called for a trainer before the final game and had her right wrist - her racquet hand - strapped, but said it was simply a precaution. 'It's happened before. I felt a pain there when I was hitting a backhand, so I called the trainer and she strapped it up for me. After that I was able to relax and it was OK.'

Kirilenko began the week as an outsider but the tournament lost its main drawcards - Americans Lindsay Davenport, Venus Williams and Russian Maria Sharapova to injury, while Serena Williams was a surprise second-round loser to China's Sun Tiantian.

'Other players had to drop out, so maybe I was a little bit lucky, but I was given a chance and I took it,' said Kirilenko.

Kirilenko's success came a day after semi-final opponent and best friend Sharapova was unable to continue due to a recurrence of a pectoral muscle problem which has bothered her intermittently for almost a year.

Groenefeld tried to stay positive. 'Naturally, I'm disappointed, but it's still been a great week for me,' said the German. 'I've had a consistent year and my ranking has gone up. I served well in the first set tonight but she just played too well.'

Before the China Open, neither Kirilenko nor Groenefeld had advanced to a final at tier two tournament. Groenefeld lost a title chance earlier this year at Pattaya, Thailand, finishing runner-up to Spanish veteran Conchita Martinez.

Kirilenko was beaten in a minor final last year in Hyderabad, India, by Australian Nicole Pratt.

She needed 53 minutes to win the opening set with a break for 4-3. But Groenefeld clawed straight back with a break to start the second. Kirilenko levelled at 1-1 with another game against serve as her opponent saved two break points before losing her edge.

Kirilenko moved up a second break for a 3-1 margin as the finish line neared, at one point leading 5-2 before Groenefeld's resistance temporarily stiffened.