They won three close sets against Dominican Republic, 25-22, 25-23, 25-23 and are the only side with a 100 per cent record in the eight-team round robin.

Hosts Japan had a day to forget however, as South Korea got the better of them 28-26, 25-17, 17-25, 25-19.

Japan had won their opening two contests but now sit second with the same record as the Koreans - who are third.

With the event doubling as an Asian qualifier, the top ranked side from the continent at the end of the round robin will automatically advance regardless of where they finish in the group.

Today's result, then, could prove to be key in the final reckoning.

Rio berths will also be secured for the three other highest teams once every match has been played.

Today's other games saw Peru record a second win as they beat a Kazakhstan side who are still searching for an opening success, 19-25, 25-22, 25-23, 25-23.

The Netherlands are the fourth team with a record of two wins and one loss after they eased past Thailand 25-14, 25-16, 25-20.