Ferrer, the No 1 seed, beat Lu Yen-Hsun 6-4, 2-6, 6-3. Each player had four breaks on the day but Ferrer had two each in the first and third sets to claim the win. Ferrer won two-thirds of the points serving while taking 16-of-30 points off Lu's serve in the decisive set.
Kohlschreiber, seeded second, edged past Alejandro Falla 7-6 (7-4), 4-6, 6-3. He had two of his three breaks in the third set, when he lost only five points on serve.
Lukas Lacko ousted eighth-seeded Thomaz Bellucci 6-3, 7-5, taking 70 percent of the points when he served.
Other second-round results Wednesday saw Gael Monfils defeat Greg Jones 6-4, 6-2; qualifier Jesse Levine advance over Brian Baker 7-5, 6-4; and Xavier Malisse, who had 15 aces, beat Santiago Giraldo 7-6 (7-5), 6-4.
Swim Week Miami Beach 2014 [PHOTOS]