Co-hosts Japan reached the second round of the World Cup for the first time to send their fanatical supporters into raptures.
In a match which largely failed to live up to an electric atmosphere inside the stadium, substitute Hiroaki Morishima gave the fans the goal they craved only three minutes after his half-time introduction.
And Japan's most recognised player, Hidetoshi Nakata, sealed the historic win and enabled a capacity crowd to start celebrating in earnest.
After Belgium's 3-2 win over Russia, Japan finish top in Group H and will now face Turkey on Tuesday.
A win was no more than Japan deserved after dominating possession against a disappointing Tunisia, who rarely looked like a side still in with a chance of progressing.
This is a victory of the Japanese spirit, of the Japanese courage and the willingness to be aggressive by taking on the opponents
Needing only a draw to progress, Japan were much the brighter team and Tunisia were only stung into a flurry of action after Morishima's goal.
Even then, it was Japan who continued to create the better opportunities and they can count themselves unlucky not to have won by more.
Japan enjoyed the majority of possession in the first half but were unable to engineer any clear-cut chances.
Junichi Inamoto was once again impressive, as he was in Japan's first two games, and made some darting runs into the box only to be let down by poor delivery from his team-mates.
But if Japan's first-half performance was disappointing, Tunisia's was baffling.
Needing to win by a two-goal margin to progress to the second round, they were strangely reticent going forward, typified by an incident midway through the first half.
Hatem Trabelsi charged down the right flank only to find none of his team-mates had made a run into the box.
Only as half time approached did they mount any serious attacks on goal.
Ziad Jaziri's long-range shot went high and wide after a slick passing move and Khaled Badra was unfortunate to see his header from a corner skim wide.
Japanese superstar Nakata sealed the win
And shouts went up for a penalty when Trabelsi dramatically went down under a challenge from Kazuyuki Toda, but the referee waved away the Tunisians' protests.
Perhaps mindful of the hot and humid conditions in Osaka, Japan coach Philippe Troussier made a double change at half time, taking off Inamoto and Yanagisawa.
And his bold move was soon rewarded when Morishima found himself space in the box and guided a right-foot shot past the stranded Ali Boumnijel in goal.
Even then, Tunisia's play was far from urgent and it was little surprise when Japan eased their nerves with a second goal, Nakata heading home from substitute Daisuke Ichikara's cross.
Tunisia: Ali Boumnijel, Khaled Badra, Hatem Trabelsi, Raouf Bouzaiene (Ali Zitouni) , Radhi Jaidi, Jose Clayton (Imed Mhadhebi), Riadh Bouazizi, Slim Ben Achour, Kais Ghodhbane, Mourad Melki (Zoubeir Baya), Ziad Jaziri
Subs Not Used: Bejaoui, Gabsi, Jaouachi, Jelassi, Marzouki, Mkacher, Mkademi, Sellimi, Thabet.
Booked: Bouazizi, Badra.
Japan: Seigo Narazaki, Naoki Matsuda, Tsuneyasu Miyamoto, Koji Nakata, Tomokazu Myojin, Junichi Inamoto (Daisuke Ichikawa), Kazuyuki Toda, Hidetoshi Nakata (Mitsuo Ogasawara), Shinji Ono, Takayuki Suzuki, Atsushi Yanagisawa (Hiroaki Morishima)
Subs Not Used: Akita, Alex, Fukunishi, Hattori, Kawaguchi, Miura, Morioka, Nakayama, Nishizawa. Goals: Morishima 48, Hidetoshi Nakata 75.
Referee: Gilles Veissiere (Fra)
MATCH STATS |
| Tunisia | Japan |
Corners (1st half) | 3 | 6 |
Corners (2nd half) | 1 | 3 |
Fouls committed | 17 | 15 |
Caught offside | 3 | 0 |
Shots on target | 1 | 5 |
Shots off target | 3 | 9 |
Hit woodwork (back into play) | 1 | 1 |
Yellow cards | 2 | 0 |
Red cards | 0 | 0 |
STOPPAGE TIME | |
First half - 2 mins | Second half - 1 min |