Rafael Nadal dispatched qualifier Ruben Bemelmans 6-1, 6-4 Thursday in his Thailand Open debut.
In his first match since winning the U.S. Open, the top-ranked Nadal lost only eight points on serve.
Nadal arrived in Thailand nine days ago, receiving a hero's welcome from government and sports officials when he landed in Bangkok. In Friday's quarterfinals, Nadal will meet either Olivier Rochus or Mikhail Kukushkin.
Second-seeded Fernando Verdasco lost to Benjamin Becker 6-4, 6-4. Verdasco, who accepted a wild card to play, fell behind 4-0 in the first set.
Verdasco dropped the ninth game of the second set on a double-fault, and Becker held serve with an impressive volley to close the match.
"It was tough. I was practicing well but the match was different," Verdasco said. "He played better than me. He adapted better than me, he served well and didn't make many unforced errors. He deserved the victory more than me."
Seventh-seeded Viktor Troicki — last year's finalist — lost 7-6 (4), 6-2 to Jarkko Nieminen.
With a first-round bye, Nadal spent time in the beach town of Hua Hin. He took part in a religious ceremony with Buddhist monks and planted a tree in King Bhumibol Adulyadej's campaign against global warming.
Back in Bangkok, he delayed a visit with Prime Minister Abhisit Vejjajiva and Parliament so he could practice. He showed no rust after completing the career Grand Slam in New York.