It was a straightforward and common footballing failing that did for the Socceroos at the Asian Cup. They simply couldn't put the ball in the back of the net.

In fact, saying it out loud makes it seem all the more simple.

Just put one of the 22 shots created over the course of a dominant performance over hosts UAE into the back of the net and Australia would likely have been facing off against surprise semi-finalists Qatar next week, after the Qataris shocked Korea Republic 1-0 in the day's other quarter-final.

However, despite the Socceroos not so much throwing the kitchen sink at their opponents defence but using it as a battering ram to repeatedly smash at a impregnable wall of Emirati defenders, not one shot managed to sneak its way through.

In fact, just two of those shots even forced goalkeeper Khaled Essa into any sort of action, as the former Asian Cup winning coach Alberto Zaccheroni's well disciplined defence held firm in the face of a significant Australian onslaught.

But not scoring goals has been a problem for Australia throughout the entire tournament.

The Socceroos failed to score in three of the five matches it played at the Asian Cup — although the impressive Apostolos Giannou did put the ball in the back of the net against the UAE, only to have it correctly ruled out for offside in the build-up.

Since winning the last Asian Cup on home soil, and playing in this one, the Socceroos only failed to score in a match in five of 35 matches.

By any measure, two shots on target out of 22 is a disappointing return.

Robbie Kruse impressed on his return to the starting line-up. ( AP: Hassan Ammar )

So what is the reason for this lack of firepower?

Do the Socceroos need a different-shaped sink to throw, or simply learn to be more effective with what it has got?

Change of tactics worked, to a point

There is no doubt the change in tactics Graham Arnold employed for this game saw a marked improvement from the dire contest against Uzbekistan on Tuesday night.

The Socceroos looked far more capable in maintaining possession with Jackson Irvine and Mark Milligan sitting deeper as part of a four-man midfield, with Robbie Kruse and Chris Ikonomidis both pushing forward on the wings.

Ikonomidis and Kruse both linked up well with full-backs Aziz Behich and Rhyan Grant, with most of the Socceroos opportunities coming from the flanks.

The change from a 4-3-3 to a 4-4-2 was necessitated by Tom Rogic's suspension, and the 'Roos definitely missed the Celtic playmaker's composure in the middle, but were still able to create enough chances to win the game.

It was converting them that was the problem.

The Socceroos were still vulnerable to counterattacks with this set-up — another problem that has been feature of the Socceroos in the UAE — but when the dangerous Ismail al Hammadi created a good chance mid-way though the first half, Mat Ryan was on hand to deny him.

All it took though, was one mistake — albeit a colossal one — for the tournament hosts to get on the scoresheet and win the game.

The dangerous Ali Mabkhout netted his 48th international goal when he pounced upon a loose back pass from Milos Degenek and rounded Ryan to score into an empty net.

The Socceroos were undone by a shocking error at the back. ( AP: Hassan Ammar )

The Al Jazera striker has an astonishing domestic goalscoring record, having scored 116 goals in 151 appearances in all competitions, and made no mistake when gifted the opportunity that won the game for the hosts.

The 28-year-old should have also scored at the end of the first half, but was perhaps caught by surprise when the ball arrived at the back post after it took a faint flick off a defender's head just in front of him.

That miss aside, what would Australia give for someone like that to lead the line going forward.

The problem is, there doesn't appear to be too many players capable of netting at that sort of rate.

Jamie Maclaren should fit the bill, but the Hibernian forward has failed to fire so far in Australian gold.

Although he is better than his solitary goal in 12 international appearances would suggest, the player who scored 40 A-League goals in 53 appearances for the Brisbane Roar just two seasons ago is yet to produce his best for Arnold.

Ali Mabkhout netted his 48th international goal in the Asian Cup quarter-final. ( AP: Hassan Ammar )

Missing players cost Socceroos

Arnold must have nightmares about the Asian Cup.

After all, this is the second time a Socceroos side lead by the former Sydney FC coach has exited the tournament at the quarter-finals stage.

On this occasion though, Arnold does have some significant caveats that he will be clinging to when the inquisition starts upon his return to Australia.

Graham Arnold was without a full complement of attacking options at the Asian Cup. ( AP: Hassan Ammar )

This Socceroos side has been severely hampered by injury, with arguably three of the best attacking players at Arnold's disposal having been ruled out of the competition entirely, with two more forced into playing a much-reduced role.

Aaron Mooy, Daniel Arzani and new man Martin Boyle were all ruled out before a ball was kicked, and Andrew Nabbout and Matthew Leckie were also hamstrung — the latter literally — by injuries in the build up that had both players operating under significant duress and not able to build game time during the tournament.

All five would all have relished the attacking opportunities that presented themselves in what was a wide open encounter at Al Ain.

Boyle in particular has been badly missed after excelling since his introduction to the international set-up at Lang Park last November.

The Scot-turned-Aussie scored twice in three matches for the Socceroos, and if not for a cruelly timed knee injury that has since ruled him out for the season, the Hibernian man may have been the wildcard to offer a staid side a much-needed injection of new ideas.

In his 18 games for Hibernian in the Scottish Premiership this season, Boyle has scored four goals and made three assists, numbers that attracted Arnold to the 25-year-old in the first place.

Martin Boyle was the Socceroos wild card until he got injured. ( Reuters: Russel Cheyne )

Add to all those injured figures the suspended Tom Rogic, and the lack of quality in the final third against the UAE begins to make a little more sense.

However, that's not the whole story.

After all, the UAE were missing their best playmaker as well in Omar Abdulrahman, but are still in the semi-finals.

A full-strength Socceroos team is still capable of performing well at the highest level in Asia, but Arnold cannot afford to make too many mistakes during qualifying, because this tournament has shown that Asian football is on the rise, and the Socceroos are at risk of being left behind.