The Brazilians are seeking to become the first country to retain the title and looked strong at the Tokyo Metropolitan Gymnasium in the Japanese capital.

After the first two sets were shared, Brazil eventually came through 25-17, 23-25, 25-23, 25-12.

Tandara Caixeta starred by scoring 28 points in the victory - 20 attacks, four blocks and four aces.

Gabriela Guimaraes and Ana Beatriz Correa scored 14 points apiece with Brazil chasing a third title at the Grand Champions Cup in all.

The country are in great form after also winning this year's FIVB World Grand Prix.

The competition features the four continental champions, the host nation and a wildcard entry selected by the FIVB.

All six will play each other in a round-robin format with the top side at the end declared the winners.

Hosts Japan, who have staged every Grand Champions Cup since the first edition in 1993, beat the FIVB's wildcard South Korea in three tight sets.

Fans at the Metropolitan Gymnasium - a 2020 Olympic venue - were left delighted after the 25-23, 25-21, 26-24 victory.

China came from behind to beat the United States 3-1.

After the Americans had started the stronger, China won 18-25, 25-18, 25-14, 25-17.

The second round of matches will be played tomorrow, also in Tokyo.

Brazil will meet China, with South Korea playing the US and Russia facing Japan. 

The remaining three matches for each side will take place at Nagoya's Nippon Gaishi Hall from September 8.