Australia stormed home with three goals in the final seven minutes for the historic come-from-behind victory in their Group F World Cup match in the city of Kaiserslautern.
It was Australia's first World Cup win and their first ever goals in only their second finals' appearance in 32 years.
The Australians looked set for a demoralising opening defeat after they were rocked by a controversial 26th-minute goal from Japanese playmaker Shunsuke Nakamura whose shot bounced in as goalkeeper Mark Schwarzer appeared to be fouled by Naohiro Takahara.
But a double from Everton midfielder Tim Cahill, who came on eight minutes after halftime, and another goal from substitute striker John Aloisi turned the game around sensationally.
Cahill fired home in a goalmouth scramble in the 84th minute after goalkeeper Yoshikatsu Kawaguchi failed to clear and he was on the spot again five minutes later to lash home a volley that rebounded off the left post into the goal.
The Japanese were reeling in the energy-sapping heat and Aloisi made the victory safe with his team's third goal, evading defender Yuichi Komano to rifle home a left-foot volley two minutes into stoppage time to send the gold-clad Australian fans into uproar.
Referee’s apology
"In the end justice was done in this game," coach Guus Hiddink said, maintaining that the Japan goal should have been disallowed.
"I think the referee will thank God for the result - it was a clear foul on the goalie."
The Egyptian whistleman Essam Abd El Fatah later apologised to both Socceroo goalkeeper Mark Schwarzer and captain Mark Viduka for getting it horribly wrong.
"He said to Dukes (Viduka) after the game, 'God was on my side', in the sense that the result went our way and it (his decision) didn't affect the result in the end," Schwarzer said. Viduka confirmed later: "He said was God was with him today."
Hiddick was delighted with the resilience shown by his players. "We are very happy, so let's enjoy this moment. I said to the boys before they went out 'You're here now in Germany, so enjoy it, but work for it.' They are so nice to work with."
Japan devastated
Japan coach Zico criticised his team for sitting back after going 1-0 up. "We did not do anything after taking the lead," the Brazilian said.
"We had two clear goal scoring chances on the counter-attack but if you do not put the ball in at one end you sometimes concede it at the other.
"The way Australia turned the game on its head is difficult for us to stomach. This is football. There is no use in stopping here and we have to prepare for the next match."
"Just being part of this World Cup means everything to all of us," said Cahill, who became the first Australian goalscorer at a World Cup after the country failed to find the net once in the 1974 tournament in West Germany.
"To get the goal is the icing on the cake but we live for moments like these. We dreamed of this when we were kids. I'm just really happy to be a part of it," said Cahill, who was the official man-of-the-match.
Australia now head to Munich next Sunday for their clash with World Cup holders Brazil, while Japan must regroup against Croatia in Nuremberg on the same day.
Hiddink, who took South Korea to the semi-finals in 2002, further enhanced his reputation as one of the great modern-day coaches with the substitutions which altered the course of the match and gave the Socceroos genuine hope of progressing to the last 16.