World No. 1 Novak Djokovic was an easy second-round winner, while third seed David Ferrer advanced without lifting his racket Friday at the Sony Open, a $4.169 million Masters 1000 event.

Fifth-seeded Juan Martin del Potro, however, was ousted in straight sets by German Tobias Kamke in the biggest upset of the event to date.

Djokovic had no trouble in disposing of Lukas Rosol, needing a mere 53 minutes to overwhelm his Romanian opponent in 6-1, 6-0 fashion on the hardcourts at Crandon Park.

The Australian Open champion and two-time defending Miami titlist beat 2009 winner Andy Murray in last year's finale here. Murray beat Djokovic in the '09 Sony Open final.

Ferrer, meanwhile, was scheduled to meet Dmitry Tursunov on Day 3, but the oft-injured Russian pulled out of the draw because of an illness.

The gritty Spaniard Ferrer will next face Italian Fabio Fognini in the round of 32.

Kamke, ranked 89th in the world, prevailed in a first-set tiebreaker before rolling in the second en route to a stunning 7-6 (7-5), 6-1 decision over the former U.S. Open champion del Potro, last week's Indian Wells Masters runner- up to Rafael Nadal.

Elsewhere, seventh seed Janko Tipsarevic of Serbia subdued Israeli Dudi Sela 6-2, 6-4 and No. 11 seed Gilles Simon downed two-time Grand Slam champion Lleyton Hewitt by a 6-3, 6-3 score.

In other action involving top-16 seeds, Spaniard Albert Ramos took down No. 12 Juan Monaco of Argentina 6-2, 4-6, 6-3, No. 13 Kei Nishikori of Japan leveled Romanian Victor Hanescu 6-3, 6-3, and No. 15 German Tommy Haas held off Dutchman Igor Sijsling 6-0, 5-7, 6-3.

Meanwhile, 19th-seeded Ukrainian Alexandr Dolgopolov erased 2008 Miami champ Nikolay Davydenko 6-2, 6-3; Belgian Xavier Malisse upended 22nd-seeded Frenchman Jeremy Chardy 6-3, 6-2; Slovenian Grega Zemlja dismissed 23rd-seeded German Florian Mayer 6-3, 7-6 (7-3); American James Blake ousted 24th-seeded Frenchman Julien Benneteau 6-2, 6-3; 26th-seeded South African Kevin Anderson earned a 6-3, 7-6 (7-4) verdict over Argentine Horacio Zeballos; Somdev Devvarman defeated 30th seed Edouard Roger-Vasselin, 4-6, 6-4, 7-5; veteran Austrian left-hander Jurgen Melzer doused 31st-seeded Spaniard Marcel Granollers 6-3, 6-4; and a 32nd-seeded Fognini foiled Frenchman Michael Llodra 6-4, 6-1.

The winner of this prestigious tournament will claim $719,160.