The 62,000-plus crowd at Saitama stadium survived anxious moments before playmaker Keisuke Honda converted an injury-time penalty as Japan salvaged a draw to grab one of the two direct qualifications from Group B.
Oman downed Iraq 1-0 in Muscat to leapfrog Australia into the second place with nine points from seven matches, turning the heat on the Socceroos who have played one match fewer and are level with Jordan on seven points.
In Beirut, a profligate South Korea eked out a 1-1 draw against a dogged Lebanese side to top group B with 11 points from six matches, ahead of Uzbekistan on goal difference.
In the same group, Iran downed Qatar 1-0 to trail the leaders by a single point as the race for the second direct qualification berth intensified.
The team that finishes third in the group can still qualify for Brazil, but must win a two-legged play-off against the equivalent finisher in Group A before another play-off against the fifth-placed team in South America.
At Saitama, Honda had his 'came-saw-and-conquered' moment as the bleach-blond playmaker converted the injury-time spot-kick after Tommy Oar had put Australia ahead in the 81st minute.
Honda had arrived in Japan only on Monday, after helping CSKA Moscow win the Russian Cup.
"It's a shame we could not get a win but I am glad we have sealed qualification for the World Cup," he was quoted as saying by Japan's Kyodo news agency.
"Lucky for us we were able to get a penalty and I was able to put it away."
The mood was different in the Australian camp where Tim Cahill admitted the road ahead was far from smooth.
"I think when you look at it we probably would have taken a point beforehand but it's just hard to take conceding a penalty," said the former Everton midfielder.
"We showed a lot of positives as a team. For us we want everyone to be upbeat and get themselves right. We have got a massive, massive game in our next one."
Much of the pressure stems from Oman, who held the Socceroos to a surprise 2-2 draw at home in the previous round and again defied the odds to down Iraq and boost their hopes of a maiden World Cup appearance.
Oman coach Paul Le Guen refused to get carried way, however, despite his team's success without star goalkeeper Al Habsi and striker Amad Al Hosni.
"We are not close to Brazil. We are closer than we were a few months ago, but I think we have a chance for third place," said the Frenchman.
"When you are coach of Oman you have to be realistic. Our league is not professional and we are in contention for third place with one game remaining."
For South Korea coach Choi Kang Hee, the main worry would be the team's poor finishing.
Stung by Hassan Maatouk's 12th-minute strike, the South Koreans mounted attack after attack in the lop-sided second half in Beirut, but had to wait until seven minutes into the added time for Kim Chi Woo's free-kick to be deflected off the wall int
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