Rain has hampered play over the first three days.
Ljubicic beat Czech Jan Hajek 4-6, 6-0, 6-3, and Querrey beat Austrian Oliver Marach 3-6, 6-4, 6-4 in a match that had been suspended because of rain Monday.
Rain completely washed out play Sunday and, combined with darkness, forced seven first-round matches to be either suspended or postponed Tuesday.
Four other seeds had their first-round matches postponed Tuesday. No. 2 Argentine Juan Monaco, No. 4 American Mardy Fish, No. 7 Croat Mario Ancic and No. 8 Dutchman Robin Haase will have to wait until Wednesday to open their play. Monaco is the reigning champion, beating Frenchman Gael Monfils in last year's Portschach finale.
Swim Week Miami Beach 2014 [PHOTOS]