A Takehiro Tomiyasu goal was enough to give Japan a 1-0 win over Saudi Arabia at Sharjah Stadium and book a place in the quarter-finals of the Asian Cup.
The defender rose highest to meet a Gaku Shibasaki corner and send a header past Mohammed Al Owais midway through the first half before forming part of a defensive rearguard that refused to be breached.
Saudi Arabia dictated play in both halves but were simply unable to finish in front of goal as the Samurai Blue defenders, marshaled by Tomiyasu and the superb captain Maya Yoshida, put in a solid shift.
Juan Antonio Pizzi's men enjoyed the lion's share of possession (77 per cent) and had 15 attempts at goal, although only one of those was on target.
"Today's key was that we could play with patience," Japan manager Hajime Moriyasu told reporters.
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Midfielder Al Dawsari had a golden opportunity to put the Green Falcons level in the 62nd minute but sprayed the ball over the bar from the edge of the area.
Moments later defender Ali Hadi Albulayhi guided the ball well over the bar with a free header after an inviting Al Dawsari cross into the penalty area.
With the clock ticking down, Al Dawsari wastefully blazed over from an excellent position after good work down the right by Fahad Al Muwallad set him up. Ali Al Bulaihi had a chance to force extra time when he was left unmarked at the back post but got his header all wrong to send the ball sailing harmlessly off target.
Despite the relentless pressure Hajime Moriyasu's side held firm to record a famous shutout, extending Saudi Arabia's title drought for a fourth continental title to at least another four years.
The defeat could be Pizzi's last match in charge of Saudi Arabia. The 50 year old, who took charge of the national team just before last year's World Cup in Russia when the Green Falcons exited at the group phase, told reporters that his contract expires at the conclusion of the Asian Cup and that so far there had been no discussions with the Saudi Arabia Football Federation on renewing it.
Japan, who claimed their last title in 2011, had won all three of the previous tournament matches in the UAE to finish top of their group, while Saudi Arabia finished second in theirs with wins over North Korea and Lebanon.
Japan next face Vietnam, who won their last-16 encounter against Jordan on Sunday via penalty shoot-out for a place in the semi-finals on Thursday.