Adam Ashley-Cooper scored a hat-trick of tries as Australia reached the final of the Rugby World Cup for a fourth time with a 29-15 win over Argentina this afternoon.
The Wallabies will face Southern Hemisphere rivals New Zealand's in next Saturday's showdown after battling past a spirited Pumas outfit at Twickenham.
In the 46th match of the tournament, Australia went over for the fastest try so far when Rob Simmons picked off Nicolas Sanchez's pass and touched down for his first-ever World Cup try with 67 seconds on the clock.
Bernard Foley was good with the conversion, while up the other end Sanchez also split the posts to atone slightly for his earlier mistake as Australia gave away one of seven penalties in the first half.
Despite getting on the board, Argentina were all at sea defensively and Australia had their second try before the 10-minute mark as Foley found Ashley-Cooper with an arcing pass and the winger went over in the corner for his 35th Test try, the third-most in Australian rugby history.
From a much tougher position, Foley converted to put the Aussies 11 points in front before Argentina, looking to reach their first World Cup final, settled down.
Their top try-scorer in the tournament Juan Imhoff had to go off injured in the 18th minute, but it didn't dampen Los Pumas' momentum as more strong play at the breakdown won them a penalty which Sanchez kicked home from out wide.
The initiative was handed back to Australia in the 25th minute when referee Wayne Barnes adjudged that Tomas Lavanini had tackled Israel Folau dangerously and the Wallabies made their numerical advantage count as Ashley-Cooper, this time out on the left, touched down for a second time.
At the other end, Sanchez's third penalty cut the gap to 10 and Argentina were close to reducing that further before the break when Joaquin Tuculet knocked on with the tryline at his mercy after Santiago Cordero had broken the Aussie line.
Argentina had to start the second half stronger than they did the first, but they gifted Australia a penalty straight away. Foley was kicking better than in the quarter-final against Scotland, but this time he skewed his attempt to let Los Pumas off the hook.
Sanchez was having much less trouble and he sent over a fourth penalty moments later to bring Argentina within seven. However, Foley quickly answered with a penalty that just made it over the bar.
Sanchez was also having joy breaking through the Australian line, but Argentina could not find that killer pass or gap of space to score a try. The fly-half's fifth penalty cut the gap once more to seven and that was how it stayed for the next quarter of an hour as the Wallabies continued to hold firm.
Victory was sealed with eight minutes on the clock largely thanks to Drew Mitchell. The winger made a lung-busting run down the left-hand side before cutting infield and weaving through multiple Argentinian challenges to set up Ashley-Cooper on the right for his third try.
That was game over, but Argentina, who miss out on a first final appearance, continued to push for a try to give their fans something to cheer about. The Aussie defence held firm, though, and they will now face rivals New Zealand for the first time in a World Cup final next Saturday at Twickenham.
