New No 1 Serena makes history
Serena Williams has been officially confirmed as the new world No 1, making history in the process.
The American, 31, is the oldest player to hold the position, beating the previous record held by Chris Evert who was 30 years and 11 months when she was top of the rankings in November 1985.
Williams is back on top of the world for the first time in two-and-a-half years.
She was usurped by Caroline Wozniacki in October 2010 but her victory over Petra Kvitova at the Qatar Open in Doha on Friday ensured she took over from Victoria Azarenka.
Azarenka, who won the Australian Open and the Qatar Open - beating Williams in the final - drops to No 2.
Williams' coach Patrick Mouratoglou said: "Her main goal is to win as many Grand Slams as she can, as she feels that she still can.
"That's her main motivation and I think she will keep that. I don't think it's hard, but she needs a few things. She needs to stay healthy first, because at 31 that's something really difficult.
"So the main thing is staying fit and the motivation. If she does those two she'll keep on improving - if she wants to. If she achieves both, I think she can still win more Slams. Why not 18? She's not that far from 18."