16-Slams winner Serena says she has not peaked

Serena Williams of the US poses with her trophy after defeating Maria Sharapova of Russia in their women's singles final match to win the French Open tennis tournament at the Roland Garros stadium in Paris June 8, 2013. Serena Williams proved an irresistible force once more as she powered past Maria Sharapova 6-4 6-4 to win the French Open for the second time on Saturday - 11 years after her first triumph.  [Photo/Agencies]

Serena Williams of the US poses with her trophy after defeating Maria Sharapova of Russia in their women's singles final match to win the French Open tennis tournament at the Roland Garros stadium in Paris June 8, 2013. Serena Williams proved an irresistible force once more as she powered past Maria Sharapova 6-4 6-4 to win the French Open for the second time on Saturday - 11 years after her first triumph. [Photo/Agencies]

Serena Williams of the US poses with her trophy after winning the French Open tennis tournament at the Roland Garros stadium in Paris June 8, 2013. Serena Williams proved an irresistible force once more as she powered past Maria Sharapova 6-4 6-4 to win the French Open for the second time on Saturday - 11 years after her first triumph. [Photo/Agencies]

Serena Williams of the US poses with her trophy near the Eiffel Tower in Paris after winning against Maria Sharapova of Russia in the women's singles final match at the French Open tennis tournament in Paris June 8, 2013. [Photo/Agencies]