Johanna Konta is through to the quarter-finals of the Dubai Duty Free Championships after a straight-sets win against Anastasia Pavlyuchenkova.
Sky Sports' tennis statisticians have been delving in the archive books and crunching the numbers in order to find out the secret of Roger Federer's success.
Petra Kvitova came from a set down to claim the Qatar Open title in Doha with a 13th successive victory.
Roger Federer celebrated his return to the top of the world rankings by winning the ABN Amro World Tennis Tournament in Rotterdam on Sunday, and declared it "very special".
Garbine Muguruza will prepare for the defence of her Wimbledon title with an appearance at the Birmingham Classic in June.