Defending champion China crushed another Asian powerhouse Japan in straight sets to advance to the women's volleyball quarterfinals on Sunday night.

Both teams had virtually qualified for the final eight after the United States outgunned Poland 3-2 in another Pool A match earlier in the day.

The Polish team, ranked fifth in the group with only one win, ended its Olympic campaign as only the top four of six teams advance.

China's 3-2 win-loss record is good enough for third in Pool A, while Japan trailed behind in fourth with two preliminary wins.

China's women's volleyball team celebrate after defeating Japan 3-0 during their women's preliminary pool A volleyball match of the 2008 Beijing Olympic Games on August 17, 2008 in Beijing. [Agencies]

Due to a slow start, China was down 12-3 early in the opening set after a series of passing and spiking errors. But China's head coach Chen Zhonghe turned the tables by replacing error-prone veteran setter Feng Kun with the younger Wei Qiuyue.

The substitution proved effective. Wei helped China's ace hitter Wang Yimei make full use of her powerful spikes with some precise setting. Wang scored nine points to help China narrow the gap 14-13.

Japan started to showcase its tenacious defense as the two sides traded leads until a 24-all tie before China took the set 26-24 on Zhou Suhong's spike and a kill block from middle blocker Xue Ming.

The host reclaimed its rhythm by strengthening its blocking against Japan's two key scorers Megumi Kurihara and Erika Araki. After a 13-3 start, the Chinese glided to a 25-16 second-set victory.

With two sets in hand and inspired by thunderous cheers of more than 14,000 home fans, the Chinese played the third set in a more relaxed way, while the Japanese could not organize an effective counterattack as they finally collapsed under China's powerful serves. China took the final game 25-14 on a middle-court spike from Xue.

Wang scored 15 points for China, and Araki contributed 10 points for Japan.

China's coach Chen admitted that setting has become the Achilles' heel of the defending champion, which is gunning for a medal in Beijing.

"It's hard for us to organize a smooth attack due to the unstable performances of our setters, which cost us dearly at crucial points, so we have to resolve this problem as soon as possible," Chen told Xinhua.

But the coach denied he would keep Feng out of the starting lineup.

"Generally speaking, she played not bad, but every player on the team should be ready for tough matches in the quarterfinals," he said.

Cuba, the US, China and Japan head to the quarterfinals in Pool A, as Poland and Olympic debutant Venezuela will head home.

In Pool B, Brazil, Italy, Russia and Serbia advanced to the final eight, while Kazakhstan and Algeria were blocked from the quarterfinals.

Xinhua