Iran sealed their place in the knockout phase of the Asian Cup on Saturday as Carlos Queiroz's side claimed a 2-0 win over Vietnam, while Iraq also booked their spot in the next round of the continental championship.
Iraq's comfortable 3-0 win over debutants Yemen saw them join Iran in advancing from group D before the pair face off on Wednesday to determine who finishes in top spot in the standings ahead of the Round of 16.
Sardar Azmoun scored twice for the Iranians, who are looking to win the title for the first time since 1976, against a valiant Vietnam in a game in which Queiroz made three changes to the side that won their opener against Yemen.
"I believe that you need to have your entire squad ready to make a contribution at any moment," said Queiroz.
"You can win games with starting line-ups but you win championships with squads. My duty as a coach is to keep the 23 players positive and with a constructive attitude."
Azmoun put Iran ahead seven minutes before the break when he headed home Saman Ghoddos' lofted cutback from close range. The Rubin Kazan forward then put the result beyond doubt in the 69th minute when he held off the Vietnamese defence before slotting into the bottom corner of Dang Van Lam's goal.
Iraq had few problems brushing aside a Yemen side that lost 5-0 to the Iranians in their first game of the tournament.
Muhannad Ali put Srecko Katanec's side in front with 11 minutes on the clock when he danced past several defenders and slammed home the ball from the edge of the area.
Eight minutes later, Besan Rasan teased the Yemeni defence before scoring his side's second goal from distance as Iraq took charge of the game, with Alaa Abbas adding a third in injury time.
In the day's late game, Saudi Arabia notched up their second win in Group E to edge closer to the next round as Juan Antonio Pizzi's side saw off Lebanon.
The 2-0 win means the Saudis will be guaranteed a top-two finish in the group and a place in the round of 16 if Qatar defeat North Korea in their meeting in Al Ain on Sunday.
Fahad Al Muwallad put Pizzi's side in front 12 minutes into the game when he smashed the ball past Lebanon goalkeeper Mehdi Khalil and into the roof of the net.
Hussain Al Mogahwi made his team's second goal midway through the second half when he slid in to nudge Hatan Behebri's perfectly delivered cross over the line from three metres out