Caroline Wozniacki wins epic battle against Venus Williams to claim WTA Finals title

Wozniacki prevailed 6-4, 6-4 and held off an inspired comeback from Williams in the second set to claim the biggest win of her career.

The 37-year-old American had held a 7-0 record over Wozniacki going into the match but the Dane put on an inspired display of serving and retrieving to claim the elite eight-woman event for a first time after losing a previous final in 2010.

"It was all going well at 5-0 in the second set, then she went for her shots and I was just so happy to get it done in the end," said Wozniacki, who will rise three places to third in the world rankings after the victory.

"Eight is my lucky number and I figured if I was ever going to beat her it would be today ... and I just went out there and did my best."

The pair traded early breaks of serve before Wozniacki won an incredible rally to break again at 4-3 in the opening set, only for Williams to hit back in the very next game.

But the Dane was not to be denied as she broke again to take the opening set.

Former World No.1 Wozniacki stepped on the gas early in the second set, breaking in the opening game and cruising into a 5-0 lead, but 10-time Grand Slam champion Williams was not going down without a fight.

Needing to hold serve just to stay in the contest, Williams found her rhythm to belatedly get on the scoreboard in the second set and then secured her first break of the second with some solid play against an increasingly anxious Wozniacki.

Williams suddenly appeared relaxed and free, holding easily to heap more pressure on the Dane before stretching every muscle and sinew in an impressive ninth game to break once more and get it back to 5-4.

The crowd wanted more but Wozniacki was not prepared to give them what they wanted, breaking again and sealing victory on her second match point with a backhand winner down the line, and tossing her racket in the air as she celebrated a stunning triumph.