NEW YORK: Reigning US and Australian Open champion Serena Williams defeated elder sister Venus Williams 6-4, 6-3 here Monday in the final of the made-for-television Billie Jean King Cup one-day tennis event.

Serena Williams won 5-of-14 break point chances over the reigning Wimbledon champion to capture the 400,000-dollar top prize in the four-woman event at Madison Square Garden.

"It was really intense," Serena Williams said. "She never gives up. That's what's so hard about playing her. She hits so hard and she runs down everything. That is what's so frustrating about her."

Venus Williams, coming off WTA titles in Dubai and Acapulco, opened by defeating 2008 year-end number one Jelena Jankovic 6-4 in one no-ad scoring semi-final. Serena beat 2008 French Open winner Ana Ivanovic 6-3 in the other.

That set the stage for a sister act showdown in the best-of-three set final.

Serena surged ahead 5-1 before Venus rallied, but Serena opened a 5-2 lead in the second set and broke Venus in the last game, claiming the trophy on her second match point.

Venus opened the door with her fifth double fault and Serena followed with a pair of forehand winners to secure the triumph.

"I tried but she was too good," Venus Williams said. "She just didn't miss and I needed a little more luck."

Each of the Serbian stars received 250,000 dollars while Venus settled for a runner-up prize of 300,000 dollars in the 1.2 million-dollar event.