Doha, Qatar (SportsNetwork.com) - World No. 1 star Novak Djokovic cruised into the second round, while on-the-mend former top-ranked great and defending champion Rafael Nadal was sent packing at the season-opening $1.22 million Qatar Open on Tuesday.

Playing his first ATP tennis since October, the second-seeded Nadal succumbed to German qualifier and fellow left-hander Michael Berrer, 1-6, 6-3, 6-4, in just under two hours. Berrer dropped his previous two matches against Nadal, with both losses coming at Masters events.

The 127th-ranked Berrer broke Nadal to go ahead 3-1 in the second set, and then in the first game of the third.

Berrer had never before beaten a top-five player. The 34-year-old father of two has already announced he's retiring at the end of this year.

"It's really unbelievable," Berrer said. "It's my last season so I'm just going for it. Why not?"

The 28-year-old Nadal missed several months of action last season while battling wrist and back injuries, as well as an appendectomy.

"These things happen after long time without being on the road, being on rhythm, being in competition," Nadal said. "I was playing with more nerves because after long time (away) I wanted to win.

"When you are back from an injury, that takes time."

Nadal beat France's Gael Monfils in last year's Doha finale and was the runner-up here in 2010.

Meanwhile, the top-seeded Wimbledon champ Djokovic drilled fellow Serb Dusan Lajovic 6-2, 6-1 in 59 minutes on the hardcourts at Khalifa International Tennis Complex. His second-round opponent on Wednesday will be Ukrainian Sergiy Stakhovsky.

In other first-round action involving seeds, No. 3 Tomas Berdych topped Uzbekistan's Denis Istomin 6-1, 6-4; No. 4 David Ferrer snuck past Dutch qualifier Thiemo de Bakker 6-7 (4-7), 6-4, 6-3; Jan-Lennard Struff ousted No. 5 fellow German Philipp Kohlschreiber 7-6 (7-3), 4-6, 6-1; and Italian Andreas Seppi upended No. 8 Leonardo Mayer 5-7, 7-6 (7-4), 7-6 (7-4).

Also on Day 2, Stakhovsky whipped wild card Jabor Mohammed Ali Mutawa of Qatar 6-1, 6-1; Slovenian qualifier Blaz Kavcic beat Argentine Juan Monaco 7-6 (7-3), 6-4; Brazilian Joao Souza overcame Tunisian wild card Malek Jaziri 3-6, 6-4, 6-3; and Georgian qualifier Nikoloz Basilashvili surprised Russian Mikhail Youzhny 7-5, 6-2.

Doha serves as a tune-up for the Australian Open.