Top seed Tomas Berdych returned to the Thailand Open after half a decade's absence Wednesday with a hard-fought 6-3, 6-3 win over Roberto Bautista Agut to reach the quarter-finals.
The world number six Berdych, who this month helped the Czech Republic into a second straight Davis Cup final, took revenge for a loss to the Spaniard Bautista Agut in January in Chennai.
After an opening-round bye, Berdych spent 41 minutes in winning the opening set and saved break points in his first two service games of the second on his way to victory.
"I faced some tough moments, but I reacted well," he said. "It was a long trip down here but I felt good in the match, I've had good practice and I'm ready to play."
Berdych drew a time violation trailing 0-40 on serve in the third game of the second set after the ballgirls appeared not to be quick enough.
But he got out of trouble in the game to hold and said it didn't take much to re-establish his rhythm.
"You cannot blame the ballgirls, they are trying their best. But sometimes it can be a matter of seconds," said the Czech.
Sixth seed Feliciano Lopez and Igor Sijsling of the Netherlands also booked their places in the quarter-finals.
While Lopez went through without problems over Japan's Go Soeda, 7-6 (7/5), 6-3, there was plenty of hard work for Sijsling, who beat compatriot Robin Haase for the second time this season as he posted a 6-7 (7/9), 6-4, 7-6 (7/2) second-round win which took two-and-a-quarter hours.
Sijsling, ranked 75th to the 60th of Dutch number one Haase, said: "It went well but it was a very tough match and we both played well. He got a bit defensive and tried to make the points longer, physically it was tough."
"I tried to play attacking tennis and it worked for me. I got to the net more and I think that helped in the end," added the Bangkok debutant.
In concluding first-round play at the hard courts of the Impact Arena, Russian fifth seed Mikhail Youzhny struck six aces and saved all three break points in a 6-3, 6-2 defeat of Italian Paolo Lorenzi.
Making his tournament debut, Youzhny will next play Uzbek Denis Istomin, winner over South Korea's Jeong Suk-Young 6-3, 6-0.
Youzhny, 31, is one of 14 over-30 winners on the ATP this season. He now stands 33-20 in 2013.
Lu Yen-Hsun of Taiwan moved into the second round after defeating another Russian, Evgeny Donskoy, 6-3, 6-2.