Sharjah: A first-half goal from Takehiro Tomiyasu was enough to send Japan into the Asian Cup quarter-finals for the eighth consecutive tournament after a 1-0 win over Saudi Arabia at Sharjah Stadium on Monday.
The Saudis, looking to end a 23-year drought since their third continental title, paid the price for failing to convert their chances and so the four-times champion Samurai Blue progress to face Vietnam on Thursday.
Japan went in front in the 20th minute when defender Tomiyasu rose above a Saudi defender in the centre of the box to head a corner into the bottom left-hand corner of the net.
The Samurai Blue defenders put in a solid shift against an aggressive Saudi Arabia, who dictated play throughout the match but struggled in front of goal.
"Today's key was that we could play with patience," Japan coach Hajime Moriyasu told reporters.
Midfielder Salem Aldawsari had a golden opportunity to put the Green Falcons level in the 62nd minute but sprayed the ball over the bar with a right-footed shot from the centre of the box.
Moments later defender Ali Hadi Albulayhi guided the ball well over the bar with a free header after an inviting Aldawsari cross into the penalty area.
The defeat could be Juan Antonio Pizzi's last match as Saudi Arabia head coach. He told reporters that his contract expired at the Asian Cup and that so far there had been no discussions on renewing it.
Japan, who claimed their last title in 2011, had won all three of their previous tournament matches to finish top of their group, while Saudi Arabia finished second in theirs with wins over North Korea and Lebanon.