Kuznetsova effectively used her booming forehand early, but had to survive losing leads of 4-0 and 6-3 in the second-set tiebreak. Kuznetsova played tight on all of her four match points in the tiebreaker, including double faulting twice, before Radwanska closed out the second set.
The 21st-ranked Russian won her first title since she defeated Radwanska in straight sets at Beijing in October.
"This just made me stronger," said Kuznetsova. "It didn’t kill me, I didn’t kill myself in the third set."
Kuznetsova, who has 13 career titles, became only the second player ranked outside the top 10 to win this event here since 1989.
Radwanska, ranked No. 10, was playing in her first final since losing to Kuznetsova at Beijing. She has not won a title since June 2008 at Eastbourne.
"After a match like this, it’s always disappointing when it’s a long, very tough match," Radwanska said. "I think it’s much easier to lose 6-1, 6-1 and have no chance. But if it’s a match like this, it hurts."
Kuznetsova, the two-time Grand Slam champ, appeared to be on her way to a straight-sets victory when she went ahead 5-3 in the second set. But Radwanska came back to twice hold her service, sandwiched around a service break, and take a 6-5 lead.
In the 12th game, Kuznetsova hit a forehand—one of her 51 winners—down the line to tie the set at 6-all and force the tiebreak.
That’s when things got interesting.
Kuznetsova won the first four points and when Radwanska committed consecutive unforced errors, she reached match point at 6-3.
But Kuznetsova melted down.
"My knees were shaking," she acknowledged.
On three straight match points, Kuznetsova double faulted, netted a forehand, and sprayed a backhand far wide.
Radwanska then double faulted to give Kuznetsova a fourth match point at 7-5. But Kuznetsova double faulted again before Radwanska hit a forehand winner and Kuznetsova hit a forehand volley short of the net to end the set.
"I think I did choke for the very first time in my life," Kuznetsova said. "I never had this choke before. I don’t know why it happened. Here I couldn’t make a ball."
Kuznetsova took a break in between the second and third sets and it seemed to help calm her.
"I definitely allowed my emotions to go in the locker room," she said. "But then down on the court, everything is in the locker room, and I started all over again."
She came out and held her serve at love in the first game. The pair were on serve after a trade of early breaks when Radwanska hit wide to give Kuznetsova a break and a 4-2 lead.
"It was like starting all over again," said Kuznetsova. "You let her come back, you let her see you choke. You have to be doubly stronger in the third set, and I was because I believe I am strong enough."
On her fifth match point three games later, Kuznetsova hit a backhand winner down the line to end the 2-hour, 35-minute match.
"She was playing very powerful shots and she was pushing me around." Radwanska said. "It was hard to play. She’s a very good baseline player. It’s hard to have good rallies with her."
Kuznetsova not only had the edge in winners (51-44) but committed 25 unforced errors compared to Radwanska’s 38. She holds a 7-3 edge in career matches against Radwanska, including a 5-2 edge on hard courts.
When the new rankings are released, Kuznetsova is projected to move to No. 17, while Radwanska is supposed to move up one spot to ninth.