The Louw down: Springboks lean on inside knowledge of England players

De Klerk moved to Sale in 2017 alongside Curry, while Louw is entering his ninth season with English Premiership rivals Bath where he packs down with Underhill.

The English duo have been the stand-out back-row performers at the World Cup, powerful over the ball and both capable of the dominating style of tackle coaches so like.

Insider knowledge on the two flankers was invaluable, according to Bok coach Rassie Erasmus.

"The knowledge of our players playing with those guys at the clubs is definitely going to be a bit of a benefit to us," he said.

"But on the flip side for them, playing with our players nullifies that a little bit."

De Klerk and Louw aside, other Boks playing in England include hooker Schalk Brits and prop Vincent Koch, both based at Saracens -- a club that has seven players with England. Lock Franco Mostert plies his trade at Gloucester, while full-back Willie Le Roux is at Wasps and scrum-half Cobus Reinach Northampton.

"Tom has been absolutely amazing for England this year," de Klerk said of 21-year-old Sale team-mate Curry.

"I don't think he's missed one minute for them. He's always willing to work hard and always up there with most of the stats.

"I know him pretty well now and I've got some stuff I can share with the group so that's always a positive."

Louw said his first impressions of Underhill, 23, were that he was a softly-spoken, quiet person.

"He loves a beer and I've joined him for many of those!" he added.

"He's massively developed as a player. He's refined elements of his game that definitely came through in last week's game, especially on defence. His ability to stop momentum in the tackle, his presence at the breakdown with poaching and jackalling the ball and just discovering what rugby's all about.

"He's got a massive hunger to learn and grow as a player."

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- 'Different outlook' -

England full-back Elliot Daly contested, however, that while it was good to speak to the likes of Curry about de Klerk, "when you get into these games, you are not thinking about that".

"It gives us a little insight but it probably gives them an insight into us as well," said Daly, who added that he loved playing with Le Roux at Wasps.

"He is very excitable on the pitch and when something is on he gets very excited and wants the ball in his hands," Daly said.

"He is definitely a threat in the back field and has a kicking game as well."

Erasmus said the tactical differences of the Premiership compared to Super Rugby had also rounded out players such as de Klerk.

"At scrum-half in Super Rugby, it's definitely a more flowing game," he said.

"In the northern hemisphere, with the conditions there, a guy like Faf can't just always play a running, fast X-factor game.

"A nine has to control kicking, the pace of the game, getting the forwards into the game, deciding when to kick when to run, when to speed it up and when to slow it down.

"Cheslin Kolbe has also learned that in France. A lot of those things you don't always learn in Super Rugby so that's some of the knowledge they bring into our team."

De Klerk admitted his game understanding changed in England.

"It's a lot more tactical on how you want to play and also the conditions that come with it," he said.

Louw described his time in England as a "fantastic experience".

"All credit to my development over there. I've been exposed to a different outlook to the game, played under various coaches and alongside some fantastic players and especially now.

"Whatever happens we'll have a good time off the field, but there's no doubt all of us will be fighting for glory on the field this weekend."