Yaser Kasim's wizardry earned Iraq a 1-0 win victory Jordan on Monday, while defending champions Japan were disappointed despite slamming four past Palestine.
The late match between the Middle East rivals looked to be heading for a gritty draw before Kasim slalomed through three defenders to scored via a deflection deep in the second half.
It was the touch of class that the game sorely needed and it sealed the points for Iraq as they strive to recapture the title they won in fairytale fashion in 2007.
Iraq now sit behind Japan on goal difference after the opening games in Group D and they will have high hopes of reaching the last eight, where they could potentially face bitter rivals Iran.
Kasim-style heroics were hardly required by Japan, who have won four of the last six Asian Cups and were up against a team playing in the continent's showcase tournament for the first time.
The match pitched European-based stars against struggling players from the blockaded Palestinian territories, and the Blue Samurai wasted little time getting off the mark in a 4-0 win.
Just eight minutes were on the clock when Yashuhito Endo rifled Japan's opener. Shinji Okazaki and Maya Yoshida also scored, either side of a Keisuke Honda penalty.
But it was not the goal avalanche that some expected from Japan, 8-1 winners over Uzbekistan at the 2000 Asian Cup, and coach Javier Aguirre admitted there was still work to do.
"I was happy and satisfied with the defence, but I saw some points to improve in attack," he told reporters. "I expect those points to be improved through the training sessions.
"What we were missing in the first half was probably speed and mobility, and the missing part I saw in the second half was middle range shots."
- 'Not satisfied' -
Man of the match Okazaki said: "As a result with four goals that was a great win, we played well. However, we could have been better.
"We are not satisfied with four goals we should have scored more. We should have played better, especially in going forwards, but overall it was a great result."
Iraq's Kasim became the second Swindon Town player to score at the Asian Cup after Massimo Luongo also scored a cracker for Australia in the tournament curtain raiser last Friday. The club team-mates were both named man of the match.
Monday also featured the tournament's first red cards after Ahmed Mahajna was sent off for Palestine and Jordan's Anas Bani Yaseen also got his marching orders.
Earlier record goalscorer Tim Cahill was named as captain of Australia, deputising for the injured Mile Jedinak, for the Tuesday's clash with Oman in Sydney.
"It's amazing, I love playing for Australia regardless of which country I'm in but to play at home, in front of my hometown fans and obviously family and friends is very special," said Cahill.
"But with me, not a lot of emotion comes into it when I cross that white line. I feel that it's going to be a massive game for us... there's a lot on the line."
Victory could put Australia into the quarter-finals, provided South Korea avoid defeat against Kuwait in Tuesday's other Group A tie.
Source: AFP