Olympic champion Andy Murray beat South Africa's Kevin Anderson 6-3 6-2 to reach the quarter-finals of the Cincinnati Masters.
Murray has won 20 consecutive matches ahead of the US Open, the final Grand Slam of 2016 which starts on 29 August.
The Scot will play Bernard Tomic next after the Australian beat Japan's Kei Nishikori 7-6 (7-1) 7-6 (7-5).
In the women's draw, Murray's fellow Briton Johanna Konta lost 6-7 (1-7) 6-4 6-0 to fifth seed Agnieszka Radwanska.
Germany's Angelique Kerber reached the last eight with a 7-6 (7-5) 6-4 victory over Barbora Strycova and will play Carla Suarez Navarro.