Istanbul: Serena Williams capped off a season to remember by capturing her fourth WTA Championship title with a 2-6 6-3 6-0 win over Li Na on Sunday.
The 32-year-old American finished off a dominant year, in which she also won the French and US Opens, by scooping up her 11th title of 2013.
China`s Li, whose run to the final helped her to climb to third in the world -- thus becoming the highest-ranked Asian woman ever -- broke the Williams serve twice in the first set.
However, the world number one shifted gears in the second set to roar through 6-3.
Williams showed little signs of the fatigue she complained about a day earlier, after playing more than 80 games this season, as she flattened Li in the third set with her brutal power and on court coverage.