Serena Williams admits that having love in her life has been a key to her rousing success over an exhilarating 13 months in which she has won Olympic gold, two US Open titles and a French Open.

Following a fitful night's sleep after winning her fifth US Open crown on Sunday in a three-set thriller over world No 2 Victoria Azarenka, Williams surprised a small group of reporters when asked about the power of love.

"Love? I think it's important to have it in your life, I guess. I'm not an expert on that subject," said Williams, whose stellar run coincides with her partnership with French coach Patrick Mouratoglou, who has also been linked romantically with the American world No 1.