The top-seeded American won the hardcourt tournament in 2001 and 2005 and has a 19-3 record in five appearances. He missed last year's event with an abdominal strain.
Third-seeded Russian Marat Safin and fifth-seeded South Korean Hyung-Taik Lee also won Tuesday at FitzGerald Tennis Center. Safin topped Czech Jan Hernych 6-2, 2-6, 6-2 and Lee beat Russian Igor Kunitsyn 6-7 (7-9), 6-3, 6-1.
In other second-round matches: ninth-seed Gael Monfils of France beat Slovakian wild card Martin Klizan 7-6 (7-5), 6-4; American Amer Delic, the 13th seed, rallied past Chilean Paul Capdeville, 6-7 (5-7), 7-5; and Dutchman Robin Haase squeezed past 14th-seeded Frenchman Michael Llodra, 6-2, 6-7 (7-9), 7-6 (7-4) in second-round action.
Swim Week Miami Beach 2014 [PHOTOS]