TWICKENHAM, London -- Wallabies fans hoped they'd seen the last of this type of performance, but secretly feared it would rear its ugly head at some stage during the Rugby World Cup. They can, however, breathe easy knowing their side is through to the semi-finals. Just. But the Wallabies' fortunate 35-34 win over Scotland won't have their southern hemisphere rivals in the World Cup semifinals shaking in terror.

There is little doubt the occasion got the better of the men in gold, and they must somehow now regroup ahead of a semi-final with the in-form Argentina. And certainly there won't be a more talked about calf than David Pocock's in the lead-up; the Wallabies were a shadow of the side without him.

As bad as Australia were, Scotland were the opposite. Smart and accurate. Brave and unlucky. Using the holes picked out by Wales last week, the Scots executed a simple game plan and were ruthless in capitalising on Australia's mistakes at Twickenham - two of which were gifted to them with a side of haggis.

The game was not devoid of controversy either with referee Craig Joubert enduring a number of difficult calls. The decision to sin-bin Scotland winger Sean Maitland in conjunction with the TMO will be talked about for weeks to come, as will the South African's best impersonation of Usain Bolt at full-time. He could not have got off the park any faster.

Bernard Foley of Australia kicks the match-winning penalty © Getty Images

Enlarge

Earlier, the Aussies had started so brightly. The match appeared likely from the opening moments to follow largely the script of the previous three quarterfinals -- northern hemisphere teams unable to handle the speed of their southern counterparts. But, in an early indication of the error-riddled 75 minutes that followed, Bernard Foley decided to pass to Drew Mitchell when he probably could have extended his arm and scored himself.

Despite that missed opportunity, Scotland seemed set for a long night -- and that was only reinforced when Tevita Kuridrani bumped off a feeble attempted tackle and drew the final defender to put Adam Ashley-Cooper over. Foley missed the conversion but the Aussies were away. Or so everyone thought.

From there the cracks started to show. Scott Sio's horror night at scrum-time began and Scotland skipper Greg Laidlaw started popping the penalties that would give his side an unlikely 16-15 lead at the break. The underdogs did manage one five-pointer in the first half with Peter Horne doing what 15 Welshman were unable to do seven days earlier simply by picking the ball up and running straight through the middle of the ruck. What Wales coach Warren Gatland must have been thinking.

Australia responded with two tries of their own before the interval, with their driving maul effort on the stroke of half-time looking to be particularly crucial. So did Foley's third failed conversion.

Everything looked good for Australia when Adam Ashley-Cooper posted their first try © Getty Images

Enlarge

If the first half had shocked the 77,110 on hand, it was merely a foretaste of what was to come after the break. And Maitland's yellow card just two minutes after the resumption was just the beginning. A short while later Genia -one of the few Wallabies to keep his head - found Drew Mitchell for the second of his two tries. That would have been the end of previous Scotland sides. But this is a different outfit under Vern Cotter.

With Maitland still in the bin, the Wallabies were left to rue a little breakdown knock-on that nullified Ashley-Cooper's try in the corner. The TMO had entered the game and the Wallabies' sanity went in the opposite direction; just when they needed to compose themselves, they completely lost the plot.

Taking the blindside option from possibly the only solid Wallabies scrum of the match, Foley opted for a chip kick only to see it charged down by Finn Russell. The Scottish No.10 set off for the line before he popped the ball up to Tommy Seymour, who crossed in the corner. Foley's failed chip portrayed the pressure of the situation perfectly. But what followed was beyond comprehension.

Kuridrani claimed the Wallabies' fifth try after a succession of phases, but Laidlaw was able to cut the gap by three again when he knocked a penalty over with 11 minutes to play. And that turned out to be exactly the right call when replacement Wallabies prop James Slipper threw a no-look pass and Scotland centre Mark Bennett picked off an intercept. Laidlaw converted and the Wallabies looked to be heading home -- their unbeaten pool run ending at the first whiff of knockout rugby, their hopes of a third Webb Ellis crown washed away in the rain that had started to fall just a few minutes earlier.

But there was still time for one last moment of drama.

We will debate endlessly whether Joubert's decision, in which he judged a Scotland player to be offside following a flurry of arms from a loose lineout ball, was correct; those from north of the borders will think it wasn't, and they may have a few unlikely allies down south if the Twickenham crowd was anything to go by. But the penalty still needed to be kicked and Foley, who was off line for much of the night, deserves credit for doing just that.

So the Wallabies escaped with a victory. But they don't deserve praise for their performance. They may have scored five tries to three, and dominated possession and territory, but there was a distinct lack of composure and commonsense when they needed it most. And it only gets more intense from here.