MIAMI, FL, USA - Victoria Azarenka held on in a tight three-setter against Svetlana Kuznetsova on Thursday to reach the final of the Sony Ericsson Open, the biggest Sony Ericsson WTA Tour final of her blossoming career. Serena Williams is up next.

Azarenka, the No.11 seed at the prestigious $4.5-million tournament, had not beaten the No.8-seeded Kuznetsova in any of their three previous encounters, but this time came out swinging, taking the first set, 6-3. Kuznetsova used her greater variety - which includes a world class repertoire of topspin and slice from the baseline, crafty net play and one of the best serves around - to retaliate with a win in the second set, 6-2.

Azarenka grabbed a break in the first game of the third set and held onto it until she served for the match at 5-4. At 30-all Azarenka ran down several angled shots and eventually fired a screaming forehand pass to bring up her first match point, and although she squandered it and got broken back, she would regroup to break again in the next game, then serve the match out, 63 26 75.

"The second set didn't go so well for me, but I still hung in there and played for every point, no matter what," Azarenka said. "When it got back to 5-all, I just thought that I had to keep going, no matter what. She played well on the match points, so it's not something I lost. I'm so happy I found the energy to fight at the end. It wasn't so much energy in the last few games, more like adrenaline. It was getting really, really tough to even walk through the last points."

"I've got to improve some things, but I'm definitely back in the game," said Kuznetsova, whose pre-Miami results this season were far below her par. "I felt the ball and did the things I wanted to on the court here. I was fighting all I could and today I maybe just didn't serve that well in the third set. But I was fighting."

This will be Azarenka's seventh and biggest career singles final on the Tour. She lost her first four - two in 2007, two in 2008 - and has won her last two, both this year, at International-level tournaments in Brisbane and Memphis.

The Williams sisters took the court at night in the second semifinal, with the No.1-seeded Serena taking out No.5-seeded Venus in a see-saw three-setter, 64 36 63. In an entertaining display of power tennis, younger sister Serena evened up her head-to-head against Venus, 10-10. She also secured her stay as world No.1, which she would have lost to Dinara Safina had she lost in the semis; also, she took a step closer to her third straight Sony Ericsson Open crown.

"It's definitely good to even it up. I would love to be in the lead again," Serena said of the Williams head-to-head. "I was also thinking I'd love to remain No.1, so obviously I'm really excited about that. I think I was more happy about that than winning the match at the end. I'm really happy to get over this one."

"It was a well-fought match. My serve wasn't going as well as I wanted but she brought a lot of balls back and played really tough," Venus said afterwards. "When I come to a tournament I come to win. So I'm disappointed right now. But I'm looking forward to working hard and doing better next time."

Serena Williams and Azarenka have played two times previously. In their first meeting, Williams won routinely, 63 64, in the third round of the Australian Open in 2008; in their second meeting, in the fourth round of the same event this year, Azarenka won the first set, 6-3, but was trailing 4-2 in the second set when she had to retire due to dizziness and illness. Williams went on to win the title.