Paralympic champions Australia began their BT World Wheelchair Rugby Challenge campaign with a 65-62 victory over Japan at London's Copper Box Arena.
The teams were closely matched throughout the contest but the world number one Australians were slightly ahead of their rivals at the end of every quarter before eventually closing out the contest.
Daisuke Ikezaki scored 29 tries for Japan but his efforts were to be in vain in the Pool B encounter, which also saw his country take to the London 2012 Paralympics venue for the first time in the tournament.
Australia then returned to the action in the evening session where they beat hosts Great Britain, who began with victory over France yesterday, 57-55 in another tight battle.
Elsewhere New Zealand, who perform a haka before their matches, were in action twice in Pool A in the early session.
They began with a comfortable 64-32 win over South Africa, but were then beaten 54-45 by the United States who bounced back from their opening night defeat to Canada yesterday.
The US and South Africa then squared off and it was another big defeat for the latter, with the Americans winning it 62-23.
The five-day tournament is taking place for the first time and coincides with the Rugby World Cup which is also ongoing in England.
At the end of the group stage, the top two countries in each pool will progress through to the semi-finals.
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