NEW YORK: Former champion Naomi Osaka was at her free-swinging best as she stormed into the U.S. Open quarter-finals with a 6-3 6-4 win over Anett Kontaveit on Sunday. In a battle of baseline blasters, fourth seed Osaka had the edge in firepower over 14th seed Kontaveit in the late match at Arthur Ashe stadium. Kontaveit showed grit to save five match points at 5-4 in the second set but bowed out netting a forehand at the end of another baseline skirmish. Osaka’s left thigh was heavily strapped as she continues to manage a hamstring injury but she moved superbly to set up a clash against unseeded American Shelby Rogers.