World number one Aryna Sabalenka suffered a shock defeat to Ekaterina Alexandrova at the Qatar Open, granting an opportunity to the chasing pack in the WTA rankings to catch her.
Novak Djokovic is set to return to action at the Qatar Open later this month after a quicker-than-expected recovery from his hamstring injury.
Andy Murray's prospects face increased scrutiny following his second-round defeat to teenager Jakub Mensik at the Qatar Open.
Andy Murray snapped a six-match losing streak as he beat Alexandre Muller 6-1 7-6 (5) in the first round of the Qatar Open.
Iga Swiatek will take on Elena Rybakina as she bids for a third consecutive title at the Qatar Open.
Naomi Osaka was left to rue missed opportunities as veteran Karolina Pliskova edged her in the Qatar Open quarter-finals on Thursday night.