Argentina lock Guido Petti was left surprised by the lack of northern hemisphere representation in the World Cup semifinals -- but insisted the gap to their southern counterparts was "tiny".

For the first time in the tournament's history, a quartet of southern hemisphere superpowers have monopolised the World Cup semifinals with Australia, Argentina, South Africa and defending champions New Zealand taking up the final four spots in England.

This unique situation has provoked debate over whether the divide between north and south is growing instead of shrinking. However, Petti does not believe that is the case.

"I'm surprised [by the lack of northern hemisphere sides in the semifinals]. European rugby is very tough," Petti said at Argentina's Pennyhill Park base ahead of Sunday's semifinal against the Wallabies.

"Maybe southern hemisphere rugby is more dynamic. But when I play against European nations, after the match I feel more tired. It's more physical.

"If I had to say, you get a lot more of the ball in southern hemisphere rugby than you do in Europe. But European rugby is the toughest rugby in the world. They play at a great level and the differences between [north and south] are tiny."

The Pumas enjoyed an impressive quarterfinal victory over Ireland last weekend to reach their second semifinal in the last three World Cups. While their bronze medal finish in 2007 came as a shock, this time around has been far less so.

The emergence of a high performance system in Argentina, combined with their 2012 introduction into the Rugby Championship, is beginning to pay dividends. Former England international Les Cusworth was Argentina's high performance manager between 2006 and 2013, in which time he helped establish several development academies throughout the country.

Petti, 20, is part of a young, emerging Argentina squad that will likely peak at the 2019 World Cup in Japan and holds this approach in high regard.

"It was very important. Now, at 17 years old, we are getting more prepared in the gym. We get more training during the week," Petti added.

"That makes us more professional than before because we weren't getting that until we were 21 or 22, when we played for the Pumas. There was no way of preparing yourself for international rugby. This keeps us better prepared physically and mentally than before."