Djokovic, the world No. 1, defeated Ryan Harrison 6-1, 6-2, 6-3 without seeing a break point. He won 86 percent of the points on serve, losing a mere eight points in 12 games serving.
Djokovic was very sharp, firing seven aces and committing no double faults. He landed nearly three-quarters of his first serves.
No. 4-seeded David Ferrer needed a fourth set to get past Tim Smyczek 6-0, 7-5, 4-6, 6-3. Ferrer dropped serve just three times, with two coming in the third set. However, in the fourth set he didn't allow Smyczek a break-point opportunity.
Also Wednesday, No. 10-seeded Nicolas Almagro beat Daniel Gimeno-Traver 6-4, 6-1, 6-2; 15th-seeded Stanislas Wawrinka advanced when, after going ahead 6-3, 7-6 (7-4), Tobias Kamke retired with a shoulder injury; and 16th-seeded Kei Nishikori topped Carlos Berlocq 7-6 (7-4), 6-4, 6-1.
Evgeny Donskoy won 3-6, 7-6 (7-4), 6-2, 3-6, 6-3 in making No. 23 Mikhail Youzhny the only seeded player to fall on the men's side Wednesday.
Other players advancing to the third round were: 20th-seeded Sam Querrey, No. 22-seeded Fernando Verdasco, No. 24 Jerzy Janowicz, 26th-seeded Jurgen Melzer, No. 28-seeded Marcos Baghdatis, 31st-seeded Radek Stepanek, No. 32 Julien Benneteau and unseeded Kevin Anderson.