Querrey defeated Ivo Karlovic 4-6, 7-6 (7-4), 6-4 in the only main draw match on the schedule Monday.
Both players served well, landing nearly 75 percent of their first serves and each winning about three-quarters of the point on serve. Karlovic fired off 25 aces and Querrey countered with 12.
Each player had only one break, with Karlovic's winning the first set and Querrey's, which came in the final game of the match, worth the third set.
Defending champion Jo-Wilfried Tsonga, eighth in the world rankings, is the No. 1 seed for the tournament. He had the other three top seeds, including No. 2 Gilles Simon, have first-round byes in the $620,000 tournament.
Swim Week Miami Beach 2014 [PHOTOS]