Carlos Alcaraz and Iga Swiatek, the current world number ones, will bid to defend their US Open titles they won last year, but a host of rivals will be out to dethrone them.
Coco Gauff scrapped her way to a maiden win over world number one Iga Swiatek to reach her first WTA 1000 final at the Southern and Western Open in Cincinnati.
World number one Iga Swiatek beat Wimbledon champion Marketa Vondrousova 7-6 (3) 6-1 and book her place in the semi-finals of the Western and Southern Open in Cincinnati.
Top seed Iga Swiatek fought back from a set down to defeat Qinwen Zheng 3-6 6-1 6-1 and reach the quarter-finals of the Cincinnati Masters.
World number one Iga Swiatek was beaten in three sets by Jessica Pegula in the semi-finals of the Omnium Banque Nationale in Montreal.
World number one Iga Swiatek has advanced to the semi-finals in Montreal for the first time, where she will face American Jessica Pegula.