Serena Williams coach: 'She can do better in 2014'

Serena Williams's coach Patrick Mouratoglou believes that the American can "do better" next season.

The 32-year-old world number one retained the WTA Championships on Sunday, securing a 2013 record of 78 wins and four defeats.

"We've spoken about 2014 already with goals to do better than this year because I think it is possible," Mouratoglou told BBC Sport.

Williams has won 11 titles this season.