Vienna:Top-seeded Novak Djokovic defeated Tomas Zib of the Czech Republic 6-4, 6-4 Thursday to advance to the quarterfinals of the BA-CA Tennis Trophy.
In his 13th quarterfinal of the season, Djokovic will play seventh-seeded Juan Ignacio Chela, who rallied to beat Jurgen Melzer 4-6, 6-3, 6-2.
"I certainly was not at my best today, so I am happy that I was good enough to win," Djokovic said. "The first two rounds are always difficult. But I have to raise my game to a higher level against Chela."
Djokovic hit seven aces and never was in trouble in his own service games against lucky loser Zib.
The third-ranked Serb broke Zib in the fifth game of both sets and closed out the match with an ace.
The 16th-ranked Chela reached the quarterfinals for the 10th time this season.
Melzer trailed 3-1 before winning the first set, and then broke Chela in the first game of the second. But Chela dominated the Austrian after that with strong forehands from the baseline.
Stanislas Wawrinka of Switzerland and Feliciano Lopez of Spain also reached the quarterfinals.
Wawrinka rallied to beat David Nalbandian of Argentina 5-7, 6-3, 6-1, and Lopez defeated Stefan Koubek of Austria 6-4, 3-6, 6-4.
Nalbandian, who had not played for more than a month since losing to David Ferrer at the US Open, led 5-3 but struggled to close out the first set.
In the second, Wawrinka broke twice and used his third set point to level the match. Wawrinka had three more breaks in the deciding set to wrap up the victory.
Wawrinka, who also reached the quarterfinals in Vienna last year after beating Djokovic, will next play Lopez, who won the event in 2004.
Koubek missed two break points in the first game of the third set, and was then broken while trailing 5-4 as Lopez converted his fifth match point.