Ljubicic, seeded third, came from behind to beat German qualifier Philipp Kohlschreiber 6-7 (3-7), 6-3, 6-3. Ljubicic became the highest seed when Roger Federer and Rafael Nadal pulled out, both citing fatigue.
Blake, seeded fifth, snapped a five-match losing streak by holding off former world No. 1 Spaniard Carlos Moya 6-3, 3-6, 7-5. Blake hadn't won a match since playing in Miami in March.
Eighth-seeded Spaniard Tommy Robredo defeated Czech Jiri Novak 6-3, 6-2, and Serbian qualifier Novak Djokovic beat 10th-seeded Argentine Guillermo Coria 6-3, 3-6, 6-3. Coria won here in 2003 and was the runner-up in 2004.
Swim Week Miami Beach 2014 [PHOTOS]