For the last 10 years, Duane Vermeulen has owned the Springbok 8 shirt.

The Ulster back row turns 36 next month, but even at that age he still has a huge influence on the game, having fitted in well since his move to Belfast in December.

He will still more than likely be part of Rassie Erasmus's squad for their summer Test series against Wales, and subsequent Rugby Championship, as he targets one more World Cup before retirement in 2023.

His place in the Springbok team isn't certain anymore though, and it's not through any fault of his own.

Evan Roos is the new kid in town, and while Erasmus had held out on calling up the 22-year-old for the last year, his URC form has been impossible to ignore, with the Stormers number 8 recently drafted into the Springboks training squad ahead of the upcoming Test window.

Roos has been the form eight of the season, leading the league in both successful carries and defenders beaten, and that combination of power and grace saw him named the 'Next Gen Star of the Season' for the United Rugby Championship.

Tomorrow, master comes up against apprentice in Cape Town, as Vermeulen and Roos (below) pack down at the back of their respective scrums for Ulster and the Stormers, Vermeulen himself returning to the club he spent six years with earlier in his career.

"There's big talk about him and he's an exceptional player, he plays well in the Stormers set-up, he’s a big ball-carrier for them," the Ulster veteran said of his fellow South African.

However, while many are predicting Roos to be Vermeulen's long-term replacement with the Boks, the 35-year-old says that's where the comparisons end.

"We play completely different styles, he’s out running in the backline from lineouts and things like that where I’m with the forwards.

"You can maybe match him and Nick Timoney, or him and Marcus [Rea] against one another, but he’s been really influential in their game plan and racked up a couple of man of the match performances.

"It’s really good for them, he’s playing well and hopefully he gets an opportunity in the national squad, if you play well you need to get an opportunity somewhere else and hopefully it’s in national colours."

It's not the first time this season the pair will have butted heads, with the Stormers claiming a controversial 23-20 win when the sides met in Cape Town during the regular season.

That win for the Western Province franchise was a third in a row for them, while John Dobson's side followed it with six more consecutive victories, their last defeat being a February loss against Connacht at the Sportsground.

Their blistering form in the second half of the season is a stark contrast to the mood around Cape Town in September, when they started with consecutive defeats to Benetton and Munster, while the Western Province rugby union was mired by financial trouble.

"Firstly, I think everyone knows the situation WP was in, moving from Newlands to a new stadium. It was a difficult task for them but the way the players have come above that and said 'we're going to make the step up' is a really good thing to see," added Vermeulen.

"They've got some older gents back giving those younger guys some guidance and there's a good cohesion to their squad. It's well done to the players and the coaches. They've surprised a number of people and number of teams this season. Sometimes it's good to be the underdog, sometimes people can forget a team about that."

He clearly has a strong affinity to the club, having played at Newlands between 2009 and 2015, but that will be parked tomorrow afternoon as he looks to help Ulster get back to a URC final, and move a step closer to potentially their first piece of silverware in 16 years.

But in order to do it, they'll need to marry the best features of their recent wins against both Munster and the Sharks.

"The Sharks game was completely different. They have that forwards pack and they wanted to dominate. We had to take a step up and I feel that we did as forwards. It was a lot more physical up front than it was in the backs.

"Against Munster, our backs put their hands up and said we want to take it to them and you didn't really see anything up front apart from one or two scrums and one or two mauls, nothing major.

"Hopefully this weekend we can put the whole package together, not just a good backs performance or good forwards performance."

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