SAPPORO, Japan, Oct. 3 (Xinhua) -- Having played four games each, six of the 24 teams participating in the 2018 FIVB Volleyball Women's World Championship stayed unbeaten as of Wednesday.

The six teams are the Netherlands from Pool A, Italy and China from Pool B, the United States and Russia from Pool C, and Serbia from Pool D.

China recovered from a sloppy start to edge Bulgaria 3-1 for their fourth straight win at the World Championship here on Wednesday. The scores of the four sets were 22-25, 25-22, 25-14, 25-17, respectively.

The two teams previously had five encounters at the World Championship, with China winning in straight sets in the last three ones.

But the match Wednesday didn't start in China's favor, with Bulgaria building an early lead and China, despite their efforts, failed to catch up and lost the set 22-25.

In the second set, China managed to pull their acts together, and after a 22-22 tie, China got a point through a successful challenge, and then Yan Ni's block and Zhu Ting's kill helped China win 25-22.

In the following two sets, with Zhu Ting back on fire and Bulgaria making more mistakes, China sealed the victory 25-14 and 25-17.

"It was a really good game today. Bulgaria did well, especially in blocking and receiving. We learned a lot," said China coach Lang Ping after the game.

"We sent a lot of younger players to the court today and I hope the team will be able to improve," she added.

Earlier in the day, Italy outclassed Turkey 3-0, while Canada edged Cuba 3-1.

China will play Italy in their last Pool B match on Thursday. The two teams, both with four straight wins, will fight for the top spot of Pool B.

In the Pool A games held in Yokohama, the Netherlands trounced Argentina 3-0 for their fourth straight win, while Germany cruised to a 3-0 win over Mexico, and host Japan defeated Cameroon in straight sets.

In the Pool C matches in Kobe, reigning champions the United States edged the resilient Thailand 3-2 after an intense game, Azerbaijan defeated in straight sets Trinidad and Tobago which played in the Women's World Championship for the first time, and Russia beat South Korea 3-0.

Both with four losses, South Korea and Trinidad and Tobago have lost any chance to qualify for the second round of the tournament.

In the Pool D matches held in Hamamatsu, Serbia continued the winning streak by beating Kazakhstan 3-0, the Dominican Republic defeated Puerto Rico 3-0, while Brazil held off Kenya 3-0.

The 2018 FIVB Volleyball Women's World Championship kicked off on Sept. 29. During the tournament that runs through Oct. 20, 24 teams from five continents have been scheduled to compete in 103 matches.

The teams play in four groups, with six in each group, in the first round and the top four teams of each group will advance to the second round.