Serena Williams of the US reacts during her WTA tennis championships final match against Li Na of China at Sinan Erdem Dome in Istanbul, October 27, 2013. [Photo/Agencies]

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.

Li Na of China hits a return to Serena Williams of the US during their WTA tennis championships final match at Sinan Erdem Dome in Istanbul, October 27, 2013. [Photo/Agencies]