DUBAI, United Arab Emirates--Japan and Iran became the first two teams to advance to the Asian Cup semifinals on Thursday.
Four-time champion Japan eliminated Vietnam 1-0 in their quarterfinal before three-time winner Iran cruised past China 3-0.
The two unbeaten winners are set to meet in the semis on Monday.
In Dubai, midfielder Ritsu Doan converted a penalty with a low left-foot shot in the 57th minute to give Japan its fifth win in five games, all by a one-goal margin.
"It is clean sheet and we go through to the next round, that is the most important." Japan captain Maya Yoshida said. "We need to improve a lot, attacking side and defensive side as well. I feel real confidence with that. But we have to be more clinical, we have to think of more details and we can handle it."
In Abu Dhabi, Iran took control with a couple of first-half goals.
Mehdi Taremi scored his third goal of the tournament to give Iran the lead and Sardar Azmoun doubled the advantage with his fourth.
Karim Ansarifard finished it off in second-half injury time.
Iran, the highest-ranked team in Asia, is yet to concede a goal while scoring 12 in the tournament.
For China coach Marcello Lippi, who won the 2006 World Cup with Italy, the loss provided a bitter end to his two-year reign.
Iran is coached by another heavyweight, former Real Madrid boss Carlos Queiroz, who still has a chance to win a title before his contract ends after the tournament.
Video reviews were introduced at the Asian Cup on Thursday for the rest of the tournament, and disallowed a first-half goal by Yoshida. VAR revealed the ball hit his arm.
Later on, it was used before the lone goal in the second half, confirming Bui Tien Dung's foul on Doan in the area.
Outsider Vietnam made the knockout stage only as the final, fourth-best third-place team from the group stage and knocked out Jordan in a penalty shootout in the round of 16.
Vietnam goalkeeper Dang Van Lam was happy with the team's achievement.
"We're OK with this result," he said. "Our country and our fans, I think, they are very happy."
Defending champion Australia faces the United Arab Emirates while South Korea meets Qatar in the remaining two quarterfinals on Friday.