In Group B, Brazil got the better of Slovenia in a five-set thriller that lasted over two hours, while Ukraine made it two wins from two in Group A with a 3-1 win against the Netherlands in a match which could have gone either way.
In a game pitting the world's number five and six-ranked sides, it was Brazil who made the better start by claiming the first set 25-17 before the South Americans twice came from behind against the Slovenians to win the second set 30-28.
But the European side battled back to win the next two sets 25-19, 25-21 as star player Anita Goltnik Urnaut came to the fore, but in the deciding set Brazil made a quadruple substitution to freshen things up and it was those changes that finally got them over the line 15-7.
After the victory, which took 126 minutes to achieve, Brazil coach Goncalves de Oliviera said: 'We analysed very carefully how Slovenia played previously and identified their best player, Urnaut. This is what we do in all of our matches, we identify the opponent's best player and try to disrupt their game.'
Ukraine, meanwhile, came back from trailing 12-8 in the first set to the Dutch and saved set points to take it 26-24, before the Netherlands levelled by winning the second set 25-15.
But Ukraine, the world number fours, then easily took the third 25-11 as Larysa Ponomarenko continued her good form at the net, before winning the game with their second match point in the fourth (25-19).
In the other match in Pool A, Japan's women were too good for Great Britain as they won 3-0. They defended excellently and, despite not possessing huge attacking power, took advantage of their chances.
In the men's competition, Great Britain secured their first victory at the Paralympic Games with a 3-0 triumph over Morocco. After the opening two tight sets were claimed by the British side 25-20, 25-19, the Host Nation wrapped up the match by taking the third set 25-12.
'It was great to win. We started slow then got better and better. That's what happened when we played Egypt, so we need to work on our slow starts,' said John Munro, one of Great Britain's star performers in the victory.
Also in Pool A, Russia produced a superb comeback from being two sets down to Egypt to claim a 3-2 victory in the last game of the evening.
In the only game in Pool B, China's men enjoyed a comfortable 3-0 win over Rwanda.