The defending champions saw off South Africa 20-7 at the Racecourse Stadium as the Australians ended the hopes of host nation Argentina with a 34-14 win.

France were brushed aside 47-26 by Argentina in their last Pool A clash but they still crept into the semi-finals as the best-runners up across the three groups.

They proved too strong for Pool C winners South Africa, who had kicked a penalty in the dying minutes of their last pool clash against New Zealand which sent the French through at the Kiwis' expense.

France's fly-half Louis Carbonel did much of the damage as he kicked five penalties, including two in the opening seven minutes to give his side a 6-0 lead.

South Africa could not get into the contest and the French crossed for the first try when Jordan Joseph finished off a rolling maul, although the conversion was missed.

A third penalty from Carbonel, who won the golden boot when France won the tournament last year on home soil, made it 14-0 but South Africa gave themselves hope with the last action of the first half.

Fezokuhle Mbatha touched down for a try at the bottom of a maul and Jaden Hendrikse added the extras from the tee to cut the deficit to 14-7 at the break.

South Africa improved after the restart but France held strong in defence and were superb at the scrum, with Carbonel adding another pair of penalties.

"It's unbelievable for the team," said France captain Arthur Vincent.

"It was a very hard game, credit to South Africa."

Australia's win came despite them playing for 50 minutes with 14 men after scrum-half Michael McDonald was shown a red card after receiving two yellows.

Ben Donaldson's penalty kicked the young Wallabies into the lead before McDonald's first card for a dangerous tackle on Rodrigo Isgro.

Joaquin de la Vega Mendia's penalty drew the hosts level but Australia dotted down for the opening try as Lachlan Lonergan set-up Harry Wilson.

Donaldson converted before De La Vega Mendia's second successful penalty left the Australians 10-6 in front.

McDonald then endured a crazy few minutes, first scoring Australia's second try under the posts which was converted by Donaldson.

He then conceded a seven-point penalty try, however, thanks to a high tackle on Isgro as the Argentine wing looked set to score in the corner.

The gap was now just four points at 17-13 but the 14-men scored another try after the break as Lonergan crossed the whitewash.

Donaldson added the extras and then scored a try himself as he dotted down his own kick forward on the counter-attack.

He again converted before adding another penalty to add some extra shine to the final score.

"We were really on the ropes, especially at the end of that first half," said Australia captain Fraser McReight. 

"Credit to Argentina they played some really good footy but I'm proud of the boys to win with 14 men."

Australia have never won the tournament and have reached the final just once, losing to New Zealand in Argentina in 2010.

The final will be held at the Racecourse Stadium on Saturday (June 22) with Argentina meeting South Africa for third-place.

Classification semi-finals were also played today with Wales edging six-time winners New Zealand 8-7 at the Racecourse Stadium in the battle to see who finishes between fifth and eighth.

England beat Ireland 30-23 at the Old Resian Club in Rosario and will now play the Kiwis.

There were also victories for Italy and Georgia at the Old Resian Club in the ninth to 12th place matches.

The Italians defeated Scotland 26-19 with Georgia edging Fiji 12-8.

All of the classification matches will also conclude on Saturday.