NEW YORK -- John Isner, the highest-ranked American man, delivered 22 aces and was broken only once in a 6-1, 6-3, 4-6, 6-3 victory over Pierre-Hugues Herbert of France in the U.S. Open's first round.

The 10th-seeded Isner converted 5 of 9 break points while saving 6 of the 7 he faced.

He is one of 11 men from the host country on Monday's schedule.

Another, Steve Johnson, advanced with a 6-4, 7-6 (2), 7-6 (5) win against Nicolas Almagro of Spain.

Isner next faces Hyeon Chung of South Korea. Johnson plays Kyle Edmund of Britain in the second round.