Any hope of an upset was soon banished thanks to a first half brace for Mehdi Taremi (12’, 23') and an unfortunate own goal by Yemen’s goalkeeper Saoud Al-Sowadi (25’).

Two more goals followed in the second half with Sardar Azmoun (53') adding a fourth having had several efforts brilliantly saved by Al-Sowadi and Saman Ghoddoos making it five with long range volley.

If any game was to test the competitiveness of an expanded Asian Cup then this was going to be it, pitting the competition's highest and lowest FIFA ranked teams against each other. Only 5,301 spectators showed up at Mohammed bin Zayed Stadium in Abu Dhabi for what proved to be an entertaining, if one sided, spectacle.

Three times winners Iran (ranked 41st) are one of the favourites to lift the trophy while Yemen (135th) only earned their place with the growth of the competition from 16 teams to 24,

In the end, the game was effectively over within 25 minutes as Iran took a 3-0 lead.

In the 10th minute Iran split Yemen’s defence open down the middle with goalkeeper Al-Sowadi producing an excellent save from Taremi's shot to parry the ball just past his left upright. It was going to prove to be a busy and difficult night for Yemen’s keeper.

Two minutes later and Yemen’s shot stopper was unable to hold on to another strike down the centre of the goal, this time from Azmoun, and Taremi was on hand to follow up the rebound and put Iran one up.

Yemen's only two shots came in the first 11 minutes when they looked lively on the break but, after that, it was all Iran and in the 23rd minute they doubled their lead. They were awarded a free kick 30m from goal and Yemen did their best to delay the taking of it.

Finally Iran’s captain Ashkan Dejagah struck it with his right foot and the ball came off the foot of the post bouncing back onto Al-Sowadi's back as he dived and into the net.

Two minutes later and Taremi scored his second. He met a pinpoint cross from the right by Ramin Rezaeian solidly with his head giving Al-Sowadi no chance.

Eight minutes before half-time and Yemen’s keeper was again in action this time tipping a shot from Omid Ebrahimi around his post.

The first few minutes of the second half was almost a personal duel between Azmoun’s eagerness to get on the scoreboard and Al-Sowadi’s determination to prevent it.

Three minutes in and Al-Sowadi produced a wonderful save to keep out a header from the Iranian forward. Four minutes later and the same happened again with Azmoun left shaking his head in disbelief as the ball was turned around the post for a corner.

However, there was finally relief for Azmoun when, from the resulting corner, he was able to tuck the ball over the line after Al-Sowadi failed to get a clean punch on the ball with it falling to the feet of Iran’s number 20 who made no mistake.

With Iran continuing to dominate substitute Saman Ghoddoos struck a volley from outside the area with enough force to make it through a crowd of players in the penalty box and into the net for the fifth.

Iran’s final thrust saw Mahdi Torabi unleash a wonderful curling shot from 30 metres out that gave Al-Sowadi no chance but cannoned off the crossbar.

In one of the toughest groups, the second match of the round takes place tomorrow when Iraq will take on Vietnam who recently became the ASEAN Football Federation champions.

With Australia losing to Jordan and South Korea scraping past Philippines 1-0 this was a convincing display by one of the competition favourites and it would have sent out a message to their rivals.