The 31-year-old American becomes the oldest ever woman to claim top spot following her run to the Doha final, moving 265 points clear of Azarenka with Russia's Maria Sharapova remaining third.

"I never thought I would be here again," she said tearfully to a cheering crowd after her victory over former Wimbledon champion Petra Kvitova on Friday was enough to guarantee her climb back to the top.