In the round of 16, Team Melli survived a nail-biter, playing to a 1-1 draw with Syria but advancing on penalties, while the Japanese defeated Bahrain 3-1.
Match preview
Despite facing a side ranked 70 places below them, according to FIFA, Iran had difficulty breaking down a Syrian squad committed to playing defensive and holding on.
It is a tactic that nearly worked, as the Iranians fired 12 efforts on target but had to hold their nerve from the penalty spot to earn their place in the quarter-finals.
Saturday will be their eighth successive trip to that stage of the competition, with Team Melli advancing past this point only once in their four prior appearances, defeating China 3-0 in 2019.
Before their game against Hong Kong in the group phase, Amir Ghalenoei had seen his side find the back of the net with ease, scoring multiple times in eight successive games prior to matchday two of this tournament, but they have since netted a goal or fewer in two of their previous three fixtures.
Team Melli have not been beaten by a side from Asia since March 2022 (2-0 defeat to South Korea), winning 12 of their last 13 matches against this region in normal time.
You have to go back over 18 years to find the last time this team earned a victory over the Japanese, beating them 2-1 in a March 2005 World Cup qualifying affair.
A shock defeat to Iraq on matchday two (2-1) seems to have woken up Japan, winners of back-to-back games in convincing fashion.
That loss is the only one that Hajime Moriyasu's men have suffered in normal time since a 2-1 defeat versus Colombia in March of last year.
Japan have scored three goals in each of their previous two fixtures, after netting just once against Iraq, while scoring multiple times in 13 of their last 14 matches in all competitions.
Making it into the last eight of this tournament is like another day at the office for Japan, who have done so in eight successive Asian Cups, losing in only two of those appearances, in 1996 and 2015.
They have only conceded in two of their previous five knockout fixtures at the Asian Cup, though the one they gave up to Bahrain in the round of 16 this year was an own-goal from Ayase Ueda.
The Samurai Blue are unbeaten in six of their last seven matches versus Iran, including a 3-0 triumph when they met in the Asian Cup semi-finals four years ago.
Iran Asian Cup form:
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Iran form (all competitions):
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Japan Asian Cup form:
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Japan form (all competitions):
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Team News
In their round of 16 clash with Syria, Iran were missing Sadegh Moharrami and Morteza Pouraliganji through injury, and on Saturday they will be without their leading goalscorer at this tournament, Mehdi Taremi, who received a second caution in stoppage time versus Syria.
There were three changes made to the Iranian lineup from matchday three to the round of 16, with Ramin Rezaeian, Rouzbeh Cheshmi and Alireza Jahanbakhsh coming into the starting 11 in place of Hossein Kanaanizadegan, Sadegh Moharrami and Ali Gholizadeh.
Taremi has scored the last three goals for Team Melli, including their only strike in the last 16, while Alireza Beiranvand made the only penalty save for either side in their round of 16 triumph versus the Syrians, allowing captain Ehsan Hajsafi to fire home the winning spot-kick.
Reo Hatate has been ruled out for the remainder of this tournament after the Celtic midfielder sustained an apparent calf strain for Japan against Bahrain, while Kaoru Mitoma saw his first action of the Asian Cup, replacing Keito Nakamura in the second half of that match.
Takuma Asano came on to collect his 50th cap for the Samurai Blue in their previous encounter, Takehiro Tomiyasu is now at 40, Wataru Endo is one away from reaching 60 and Ko Itakura hit the 25 mark against Bahrain.
Ueda scored twice for Japan in the last 16, though one was an own goal, but thankfully for him Ritsu Doan and Takefusa Kubo had already scored before that to give the Samurai Blue a comfortable triumph.
Iran possible starting lineup:
Beiranvand; Rezaeian, Cheshmi, Khalilzadeh, Hajsafi; Ezatolahi, Ghoddos; Torabi, Ansarifard, Ghayedi; Azmoun
Japan possible starting lineup:
Suzuki; Maikuma, Itakura, Tomiyasu, Nakayama; Kubo, Endo, J. Ito; Doan, Minamino; Ueda
We say: Iran 1-3 Japan
Given the injury concerns on the back end for Iran, the Samurai Blue could find their share of openings in the attacking third, while Iran might have difficulty scoring without the services of Taremi.