When World Cup contenders South Africa take on Italy in a must-win Pool B match on Friday, it will pitch hard-hitting Duane Vermeulen against Italy captain Sergio Parisse in a monstrous clash of No. 8 titans.

Along with All Black skipper Kieran Read and injured Welshman Taulupe Faletau, the pair rank among the most effective of back-row generals.

While their international routes have been quite different, both Vermeulen and Parisse remain key cogs for their teams: powerful runners, and ever-willing tacklers with a deft passing game belying their physical stature.

"He's a stalwart for their team," Vermeulen said of Parisse. "He's a fantastic player.

"He's playing in his fifth World Cup. That's a massive achievement for a man that I kind of look up to and have played against a few times."

Parisse, 36, was born in Argentina to Italian parents and handed his international debut at the raw age of 18 by then-Azzurri coach John Kirwan in a 64-10 defeat by New Zealand in Hamilton in June 2002.

Come Friday in Shizuoka, Parisse will be winning his 142nd cap, pulling clear of Ireland's Brian O'Driscoll with just New Zealand's Richie McCaw (149) ahead of him.

It will be Parisse's 138th start. He also joins an elite club, with only Samoa's Brian Lima and fellow Italian Mauro Bergamasco having played in five World Cups.

Ups and downs

Both players have seen lean periods at times in their careers. 

When Vermeulen signed for Toulon, they were three-time successive European champions, but there was no such success for him, with Toulon's closest shot at fame being twice beaten in the Top 14 finals in 2016 and 2017 respectively.

Likewise, Parisse's time at Stade Francais fizzled out. Wholesale changes and a new-look backroom staff under ex-Springboks coach Heyneke Meyer saw the Italian depart in the summer, bound, ironically, for Toulon.

Finding himself behind Pierre Spies in the pecking order, Vermeulen only made his South African debut in 2012 at the age of 26.

Now 33, the Bok won his 50th cap in South Africa's 23-13 defeat to New Zealand eleven days ago, and many feel he could be deserving of more caps than that. 

Both players have also been nominated for World Rugby's player of the year. Parisse became the first Italian nominated in 2008, before second recognition in 2013, while Vermeulen got the nod a year later.

Arguably Parisse's greatest win in a blue shirt came against South Africa in Florence in 2016.

"Do or die"

With eight days off after their 48-7 victory over Canada, and having also logged a 47-22 win over Namibia, Italy will be a force to be reckoned with, according to Springbok coach Rassie Erasmus.

"For us, this is a crunch game, and if we have to grind it out -- this is a do-or-die game -- and just beat Italy no matter how, even if it's just a drop goal, we want to get out of the pool. The win is the ultimate," said Erasmus.

As for Vermeulen, the team collective was as important as his personal battle with Parisse.

"You want to beat your opposition as a player, but also as a team," he said.

"I want to do my individual work that is set out for me to do but also I would like to contribute to the team in the way we want to execute our plan."

© Agence France-Presse