And so we have a semi-final line-up that might not have been the easiest to predict but in many ways delivers a more fascinating pair of contests than most would have predicted.

Had the form book worked out as expected it would be Japan facing Australia in Newcastle on Tuesday, and Iran taking on South Korea on Australia Day in Sydney.

And had Japan been able to capitalise on their possession and domination of the game against the UAE with some sharper finishing, and Iran not been flummoxed by referee Ben Williams' decision to send off defender Mehrdad Pouladi, leaving them to play the bulk of their quarter-final against Iraq a man short, then we probably would have had the last four that most forecast.

But such are the uncertainties of football, and the psychological drama of the penalty shoot-out, that we are now preparing for South Korea to take on outsiders Iraq on Monday, and Australia to face Middle Eastern surprise packages the United Arab Emirates on Tuesday.

Australia and South Korea will be favourites to go through to stage an Asian Cup final reprise of their Group A meeting in Brisbane, won 1-0 by the East Asians on a playing surface roundly condemned by both camps.

But with the self-belief that the two teams from the Gulf have developed over the past few weeks as they battled through to this stage, no one can say for certain which pair will meet in the title decider. My money would be on South Korea and Australia, but as far as being a punter goes, I'm a rather better journalist ...

Australia

The host nation has steadily developed during the competition and, with its second-half demolition of China in the quarter final, has shown that it is a force to be reckoned with against any Asian opposition.

Ange Postecoglou always asked to be judged not on the World Cup or the disappointing friendly match results after the Brazilian adventure, but on the team's performances and results in the Asian Cup. He is entitled to feel vindicated now that the Socceroos have reached the last four, the stage most football people deemed the minimum pass mark for the Australians.

Confidence within the camp is high, especially with talismanic Tim Cahill in such marvellous touch. The evergreen forward showed again with his brace against China – a spectacular overhead kick and a trademark header – that when he is in the mood Asian defences still cannot shackle him, despite the fact that he celebrated his 35th birthday just before Christmas.

Trent Sainsbury has settled in at the back, and he will be reunited with Matthew Spiranovic for the semi-final now the centre half has served his suspension. Virtually everyone in this squad has had game time, and Postecoglou is getting there in creating his aim – a group where the whole is greater than the sum of its parts.

With 10 goals in four games the Socceroos are averaging more than two a match although they are far from impregnable at the back, having conceded against both Kuwait and South Korea.

UAE

A real coming-of-age tournament for the men from the Gulf who have proved themselves to be not just one of the better teams from their region but one of the best in the whole of Asia.

They might have ridden their luck against Japan, who dominated much of the 120 minutes when the two met in the quarter final. But they held their nerve when it came to the penalty shoot-out and it was the Japanese superstars Keisuke Honda and Shinji Kagawa who lost theirs, the latter hitting the post, the former skying his first effort so high over the bar one could have been forgiven for thinking Rugby Union's great kicker, Jonny Wilkinson, had been shooting for the Samurai Blue.

In fact the UAE could have counted themselves unlucky to be meeting Japan in that quarter final at all, as they only lost their last group match, to Iran, in the last minute of the match: had that games stayed scoreless Mahdi Ali's team would have topped the group on goal difference and would have faced Iraq in Canberra.

Now they find themselves up against the host nation in a semi-final, and while they will be the underdogs the UAE will give themselves every chance. In striker Al Ahmed Mabkhout they have a man who showed, with his polished finish against Japan, that he knows where the target is, and midfielder Omar Abdulrahman has won admirers wherever he has played in this competition. His cheeky "Panenka" penalty in the shoot-out against Japan left onlookers breathless at his audacity. This is a young squad that is growing together.

Iraq

A mixture of the (mainly) young and fresh faced, some emerging talents and led by the inspirational figure of veteran captain Younis Mahmoud, Iraq have once again confounded the critics to make it to the last four of the Asian Cup, albeit in controversial circumstances.

They played for more than 75 of the 120 minutes against Iran in their Canberra semi-final against 10 men, and while they showed tenacity to come from behind to level at 1-1 they also showed vulnerability, twice leading in extra time only to be pegged back to 3-3 in the most dramatic game of the competition so far.

Iraq progressed through a penalty shoot-out, but the drama didn't end there as there was then a protest by Iran that one of the Iraqi players had failed a drug test during the regular season while playing in the Iranian league and therefore should have been declared ineligible, rendering Iraq's success null and void.

Iraq has a tremendous collection of talented youngsters, winning the inaugural AFC Under -22 Championship in early 2014. They also finished third at the 2013 FIFA U-20 World Cup in Turkey. The country's youngsters have also picked up plenty of individual honours, with the 2012 and 2013 AFC Youth Player of the Year awards won by striker Mohannad Abdulraheem and fullback Ali Adnan.

The previous "golden generation", which was spearheaded by Younis and cultured midfielder Nashat Akram, delivered with the 2007 title. This tournament may be too soon for their successors, but it would be folly to rule them out.

South Korea

One of the traditional big guns of Asian football, it is a mystery how the South Koreans have not captured the Asian Cup championship since their last victory in 1960. In the intervening 55 years the South Koreans have consistently been Asia's highest achievers on the global stage. They qualify regularly for World Cups and have played in every one since 1986. Their best finish, of course, was that marvellous run to the semi-finals in 2002, the year they co-hosted with Japan, when they were eventually beaten by Germany and finished fourth.

German Uli Stielike has only been in charge for a couple of months, but he has certainly brought some steel into the Koreans' play and got them organised at the back after a disappointing World Cup when they left after the group stage, having picked up only one point through a draw with Russia and conceding six goals in their three games.

In this Asian Cup they have risen to every challenge despite having lost key players to injury and illness for part or all of the tournament. The Taeguk Warriors saw off Australia in a tactically astute display in Brisbane, and have yet to concede a goal in 390 minutes of football, seeing off Uzbekistan 2-0 in their quarter final after extra time.

Stielike says his side has the talent to go all the way and break their Asian Cup hoodoo if they can develop a stronger mentality and not let the pressure they bear from home fans – who expect success every time – break them down. They go into their game against Iraq as favourites, if only because they have had a day's more rest and played in cooler conditions in Melbourne last Thursday evening. They have the quality to make the final – it is, as Stielike says, down to their mental approach.