Japan took the lead following a rather fortunate penalty award after 20 minutes as Keisuke Honda struck from the spot, with the impressive Shinji Kagawa adding a second on 33 minutes with a smart shot on the turn.
Italy responded through a firm header from Daniele De Rossi and then completed the turnaround in the first seven minutes of the second half when Atsuto Uchida put the ball into his own net and Mario Balotelli converted a penalty of his own following an even more farcical award.
A compelling, if slightly unhinged contest took another turn when Japan drew level on 69 minutes, Shinji Okazaki heading home from a free-kick, and the drama continued late on when Japan struck the woodwork twice in the space of three seconds.
But Giovinco tapped the ball home late on to take Italy through to the last four with Brazil, while Japan’s Italian coach Alberto Zaccheroni saw what would have been a late equaliser from Maya Yoshida ruled out after Japan had hit the woodwork once again.
Japan were irresistible at the start of the match, taking the game to Italy with impressive vigour. After six minutes they should have been in front when Kagawa delivered a superb cross from the left, dropping the ball over Giorgio Chiellini and onto the head of Ryoichi Maeda – but the forward nodded it straight at Gianluigi Buffon.
Kagawa came into the tournament off the back of a mixed season when he was rather underused by Manchester United but the playmaker is essential for his country and on 17 minutes forced Buffon to tip over a vicious attempt that swerved nastily in the air from 30 yards out.
Japan were swamping an inhibited Italy side and pounced on a mistake in the Azzurri backline to take the lead after 21 minutes. Mattia De Sciglio was the guilty party and when Okazaki snuck in he was brought to ground by Buffon. The keeper got a touch to the ball and was unlucky to see a penalty awarded, even if he avoided a red card; Honda stepped up to stroke the penalty home.
Cesare Prandelli sought to address his side’s underwhelming performance when removing Alberto Aquilani for Giovinco after only 30 minutes but Italy promptly conceded a second when they failed to deal with a high ball into the box and Kagawa spun to strike a brilliant effort past Buffon and into the corner of the net.
Japan were good value for their lead, but almost collapsed before half-time. De Rossi pulled one back with a firm header from a perfect Andrea Pirlo corner before Emanuele Giaccherini struck the base of the post with an opportunistic shot in added time.
Still, Italy needed only seven minutes to turn a deficit into a lead when the match resumed, with an own goal from Uchida initially drawing the two sides level. Yoshida was at fault when allowing Giovinco to wriggle away from him by the byline and the tiny forward’s cross was turned in by the sliding Uchida.
It was then Japan’s turn to suffer a harsh penalty decision as Makoto Hasebe was bizarrely penalised for handball when a shot bounced off his leg and against his arm, which was tucked behind his body. Balotelli was ruthless as ever from 12 yards as Italy took the lead for the first time.
Giovinco almost extended their advantage with a rasping effort from 20 yards that Kawashima tipped round the post but on 69 minutes, and just seconds after Prandelli replaced Giaccherini with Claudio Marchisio when Italy were ready to defend a set-piece, Okazaki got ahead of Riccardo Montolivo to meet Yasuhito Endo’s free-kick and direct a header past Buffon.
In a frantic conclusion, Japan hit the woodwork twice in three seconds when Okazaki struck the post with a firm effort from 12 yards and Kagawa inexplicably headed the rebound against the turf and then the crossbar.
Japan were punished for the miss when De Rossi prised open the defence with a glorious pass and Marchisio squared for Giovinco, who tapped home with four minutes remaining. Even then there was time for Yoshida to have a late goal disallowed as a wonderful match reached a dramatic conclusion.
MAN OF THE MATCH
Shinji Kagawa (Japan) – He may have missed a late chance but the Manchester United playmaker was otherwise impeccable, impressing with his movement, his goal and his near-perfect use of the ball.
ITALY: Buffon 5, Maggio 6, Chiellini 5, Barzagli 6, De Sciglio 5, Aquilani 5, De Rossi 8, Montolivo 6, Pirlo 6, Giaccherini 6, Balotelli 8. Subs: Giovinco 8, Abate 7, Marchisio 7.
JAPAN: Kawashima 6, Nagatomo 6, Uchida 5, Konno 6, Yoshida 5, Honda 8, Endo 6, Kagawa 8, Hasebe 7, Maeda 6, Okazaki 8. Subs: Sakai 6, Havenaar 6, Nakamura N/A.