Originally named as a substitute, the livewire Tareq was brought on in the 58th minute and duly netted a vital equaliser just two minutes later courtesy of a thunderous finish.

With the Esteghlal star to the fore, Iraq pressed for a winner and their persistence paid handsome dividends when Ali Adnan converted a last gasp free-kick to seal all three points for the Lions of Mesopotamia.

Champions in 2007, Iraq had been behind twice before Adnan’s sublime set-piece secured all three points for Srečko Katanec’s relieved charges against a highly rated Vietnam side at Abu Dhabi’s Zayed Sports City Stadium.

At a competition where, so far at least, several of the region’s powerhouses have had things far from their own way, the victory saw Iraq go second in the Group D standings, behind the Islamic Republic of Iran who top the table following their 5-0 win over Yemen a day earlier.

The 26-year-old Al Gharafa favourite scored twice on a night when the three-time Asian champions were rarely troubled by opponents making their debut in the competition as a unified nation.

Iran’s impressive victory saw them assume pole position in Group D, a flying start that Taremi believes will stand his side in good stead going forward.

In a tournament that has already witnessed several surprise results – notably Jordan’s defeat of Australia – the Portuguese tactician was thankful that the three-time champions of Asia avoided any sort of upset at the start of their Group D campaign.

Instead, Mehdi Taremi’s brace along with goals from Ashkan Dejagah, Sardar Azmoun and Saman Ghoddos helped seal a relativy straightforward victory and a provide a perfect start to Team Melli’s 14th AFC Asian Cup campaign.

Sanchez’s squad is one of the most youthful among the 24 nations represented at the tournament, with seven of the players who have travelled to the United Arab Emirates having graduated from the side that won the 2014 AFC U19 Championship in Myanmar.

And with the country continuing to build towards their hosting of the FIFA World Cup in 2022, Sanchez believes the AFC Asian Cup will be the perfect proving ground for his players.

“There is a group of players that played in (AFC U-19 Championship) some years ago and had a good achievement,” said the Spaniard, who coached the U-19 team and also worked with the country’s U-23 squad before taking over the helm of the senior side.

The Samurai Blue, heading into their first major campaign under head coach Hajime Moriyasu, may be a team in transition but that isn't going to stop them from the mission of lifting the sparkling new AFC Asian Cup trophy come February 1.

Standing in Japan's way in Wednesday's opening Group F match are Turkmenistan, whose confidence has been boosted by Jordan defeating defending champions Australia, Palestine holding Syria and the Philippines giving Korea Republic a mighty test before eventually losing 1-0.

The White Wolves will be featuring in their seventh edition of the Continental showpiece and Cuper insists his players are ready to be tested in the UAE.

“Our team had good preparation leading up to the tournament, especially our centralised camps which included high-intensity trainings. We didn’t only focus on Oman but also the tournament as a whole and I’m satisfied with how everything went,” said Cuper.

“I’m not worried that we didn’t not play any friendlies before the tournament. I made that decision for a valid reason. Sometimes players can pick up unnecessary injuries, so I didn’t want to expose my players to that kind of risk.