Doha, Qatar - Serena Williams defeated her sister Venus Williams 6-2, 7-6 (7-4) Sunday to end her 2009 season as number one in the world with a second title at the year-end Sony Ericsson Championships. The 2002 winner at the season wrap-up ended a long dry spell at the eight-woman event, where she had also beaten her 29-year-old elder sibling in group play this week as well as the Wimbledon final and a Miami semi-final in 2009.
The winner took one hour, 25 minutes to claim victory, expressing satisfaction after finally claiming a non-Grand Slam title for the first time in a year and a half.
"It feels great, I never expected to come here and do this," said Williams. "It was a tough final, but it always is when you are playing Venus."
The winner lost just five points on her torrid serve in the opening set, then sealed the victory with a winning tiebreaker as she sent a return past her sister on match point.
"I had to serve well to beat Venus," said Serena, who is awaiting her fate after an explosion against a lineswoman at the US Open which could costs her the chance to defend her Australian Open title in January.
The International Tennis Federation is investigating the semi- final incident in New York and is due to hand down a decision - and possible ban from the next major - by the end of the year.
Williams also withdrew this week form next week's Fed Cup final in Italy, choosing instead to return to Florida.
The winner had five aces and broke twice while never facing a break point.
Venus was the first player since Amelie Mauresmo in 2003 to make it to the final after losing two of three matches in the group stage.