Sunday's second semifinal is again an all southern hemisphere affair with Australia facing Argentina just three months after the Wallabies eased to a 34-9 victory on the road in Mendoza. But much has changed since then with the Pumas now playing with greater freedom in attack as evidenced by their superb 43-20 quarter-final victory over Ireland last weekend. Daniel Hourcade's side have improved with each game of the tournament after pushing the All Blacks until the final minutes at Wembley on the opening weekend of action. The Wallabies seemingly peaked a little earlier in the tournament with their superb 33-13 victory over England, before somehow finding a way to repel Wales while down to 13 men and then surviving an almighty scare from Scotland. With Australia having improved its scrum and Argentina its attack, the two sides have arguably never been more evenly matched. It's also the first time since 2003 that they've met in a Rugby World Cup, and the first time they've faced each other during the knock-out stage.

Team news

The Pumas have made just one change to the side that accounted for Ireland with centre Marcelo Bosch returning from suspension to reclaim the No.13 jersey from Matias Moroni. Bosch missed last week's quarterfinal after he was banned for a lifting tackle in the win over Namibia; the inclusion giving the Pumas a valuable long-range goal-kicking option.

Wallabies fans breathed a collective sigh of relief on Friday afternoon when David Pocock and Israel Folau were both declared fit to start. The duo still need to negotiate the captain's run on Saturday before receiving final clearance but all indications are that shouldn't prove to be a problem. The news wasn't as good for prop Scott Sio after he failed to overcome an elbow injury; his omission opening the door for James Slipper to start.

Argentina

Joaquin Tuculet, Santiago Cordero, Marcelo Bosch, Juan Martin Hernandez, Juan Imhoff, Nicolas Sanchez, Martin Landajo; Marco Ayerza, Agustin Creevy, Ramiro Herrera, Guido Petti, Tomas Lavanini, Pablo Matera, Juan Martin Fernandez Lobbe, Leonardo Senatore.

Replacements: Julian Montoya, Lucas Noguera, Juan Figallo, Matias Alemanno, Facundo Isa, Tomas Cubelli, Jeronimon De La Fuente, Lucas Gonzalez Amorosino.

Australia

Israel Folau, Adam Ashley-cooper, Tevita Kuridrani, Matt Giteau, Drew Mitchell, Bernard Foley, Will Genia; James Slipper, Stephen Moore, Sekope Kepu, Kane Douglas, Rob Simmons, Scott Fardy, Michael Hooper, David Pocock.

Replacements: Tatafu Polota-Nau, Toby Smith, Greg Holmes, Dean Mumm, Ben McCalman, Nick Phipps, Matt Toomua, Kurtley Beale.

Key head-to-head

The improvements in the Wallabies' set-piece and Pumas' attack have just about nullified what would have been seen as each side's strength while the quality of back-rows suggests neither side will hold a clear advantage at the tackle either. With that in mind, the focus clearly shifts to the No.10s and two players who maybe small in stature but possess the ability to boss a game when everything clicks. Bernard Foley did that for the Wallabies against England three weeks ago while Nicolas Sanchez is back to his best after a woeful Rugby Championship. The Argentine is the tournament's second leading point-scorer (74) while Foley sits just eight points back in third. The player who is able to better unleash the incredible attacking talent outside them and who holds their nerve from the kicking tee will have a huge influence on this one.

Key stats

*Australia have won four of the last five meetings between the two sides, including their most recent encounter in Mendoza this year

*Australia are tackling at an astonishing 98 percent success rate at this World Cup and are missing an average of just 15.4 tackles per match. The Pumas, meanwhile, can only boast an 85 percent success rate while missing an average of 25.2 tackles per match.

*Pumas winger Juan Imhoff is having a tournament to remember with the rising star recording 10 clean breaks and five tries in five appearances. Bernard Foley has made the most breaks (7) by an Australian while Drew Mitchell has four tries.

Odds

Unibet haven't taken much notice of Australia's escape effort against Scotland, installing the Wallabies as 39/100 favourites for Sunday afternoon's clash. The same bookmakers are offering 41/20 for the Pumas while the line has been set at 6.5 points.

Weather

A sunny day will become increasingly cloudy right around the 4pm local kick-off at Twickenham with temperatures to settle somewhere between 10 and 12 degrees. The players may have to deal with some light winds but rain shouldn't be an issue.

Prediction

There is no doubt the Pumas have been the great improvers of the tournament but they'll likely need to go up another gear again if they're to reach a maiden World Cup final. Three tough weeks of Test rugby seemingly took its toll on the Aussies last Sunday while coach Michael Cheika admitted he'd made some mistakes in preparing the Wallabies for their quarterfinal. That reality check should have cleared up any thoughts of complacency and boosted by Pocock's inclusion, it'll be Australia booking their place in next week's final. Wallabies by five.