Top seed Ivan Ljubicic of Croatia fired 15 aces to beat Kevin Kim of the United States in straight sets in Beijing on Thursday.

With the 6-3 and 6-4 victory, the world No. 3 player set up a clash with eighth seed Lee Hyung-Taik of South Korea in the quarter-finals of the US$475,000 China Open ATP tournament. 

"I served well," said Ljubicic at the post-match press conference. "My baseline play wasn't at top, but I tried to play aggressively, give my opponent pressure and force mistakes. It helps me win through."

Ljubicic sealed the match when 89th ranked Kim went long with a forehand after an hour and six minutes.

Earlier on Thursday, Lee Hyung-Taik rallied from one set down to beat Michael Berrer from Germany 4-6, 7-6 and 7-6.

In the third set tiebreak, the 30-year-old South Korean won seven points in a row to erase a 4-0 deficit and make it to top eight.

"It was a tough game. There was a time when it was possible that I might lose," Lee told reporters. "I told myself not to give up and I could win, so I'm happy about the result."

World No. 5 Nicolay Davydenko of Russia advanced to the quarter-finals by beating Luka Gregorc of Slovenia 7-6 and 6-2.

Davydenko played a loose game to open the first set, being broken by Gregorc, who raced to a 3-1 lead. But the Russian returned the favor in the fifth game with a break and hold serve to overtake the lead at 4-3. The hotly contested set was finally dragged into tie breaker, where the second seed outlasted 7-2.

Davydenko recovered his confidence and smelled blood with a service break at the beginning of the second set. Then the Russian asserted his dominance for a 4-1 lead and never looked back.

"The first set and second set were totally different. The rival played his best in the first while the second was disastrous to him, " Davydenko told a post-match conference.

Although the Russian only belted five aces against six for Gregorc, he still hit 10 winners against 6 for the Slovenian. And Gregorc registered as many as eight double faults and 15 unforced errors against 10 for Davydenko.

Davydenko, a semifinalist last year in his first appearance at the China Open, will next meet sixth seeded Paradorn Srichaphan of Thailand, who overpowered Japanese Satoshi Iwabuchi 6-3 and 6-1 in the last match of the day.

For the host, Chinese duo Zeng Shaoxuan and Yu Xinyuan knocked their compatriots Li Zhe and Wang Yu out of the tournament to reach the men's doubles semi-finals.

They won the game in straight sets of 6-3 and 6-1 and will face Michael Berrer of Germany and Kenneth Carlsen of Denmark next.

(Xinhua News Agency September 15, 2006)