THEY don’t come much bigger than Saracens No 8 Billy Vunipola, both physically and in terms of reputation. Which is all the more reason why his Glasgow Warriors counterpart Matt Fagerson is looking forward to this afternoon’s head-to-head at Scotstoun.

The 20-year-old Scot has nothing but admiration for the Australian-born England star, a player, Fagerson admits, he grew up watching. However, he doesn’t intend to be too star struck when the 20-stone wrecking ball swings in his direction.

“I’ve never played against him or Saracens, so it will probably be one of the biggest challenges I’ve ever come up against,” says Fagerson, who in boxing parlance, is giving away a few pounds. “It’s difficult for a player to be the perfect package, but Billy does get pretty close. He’s a pretty good ball carrier and he can smack boys in defence. I’ve had quite an extensive look at him and the rest of the back row, and there are obviously ways to exploit them. Hopefully we can do that.

“I’m only 20 and grew up watching Six Nations rugby, so I’ve obviously seen him quite a bit. It’s been pretty cool watching all the international guys, so to play against one of them will be awesome, a big challenge. I’m excited for it.”

Vunipola is only one of Saracens "galacticos". While still a novice at this level, Fagerson is wise enough to realise that being in awe of either Vunipola, or Kruis, Itoje, Farrell or Lozowski, could land you in serious bother. Better concentrating on his own tasks.

“[Vunipola] is probably the best back-row I’ll have ever played against. I played against Sam Simmonds of Exeter and his footwork lit up the park, but he got exploited a couple of times up here as well so hopefully we’re able to do the same to Billy.

“If you dwell on them as individuals and what they’ve done, you can get caught up in it and focus too much on them. You’ve got to focus on yourself. We were probably the victims of that two years ago down there [when Warriors met Sarries in a European Cup quarter-final]. We focused on everything they were going to and we changed our game to suit them. That’s what they want.

“A name’s a name but on the day, anyone can make anyone else looked stupid. We’ve just got to concentrate on us.”

While both Vunipola brothers – Billy and Mako – play today, the other Fagerson sibling, Zander, is still injured. His absence however necessitated a new arrival who might just help the Warriors cause.

“This is his [Zander’s] first week being in doing his rehab stuff. He’s come in via taxi or with one of the boys and he’s got a little scooter that he uses to fly around to and from the gym, the lazy git,” laughed Matt. “He’s been getting pampered by the physios, pampered when he gets home. He’s done a lot of gym sessions, he’s on the up, a lot brighter than what he was.

“The way he was playing before he got injured, he’s going to be massively missed, this weekend especially. But we’ve got massive faith in whoever goes out in the jersey. D’Arcy [Rae] has been playing really well, he’s a very big and physical guy.

“Petrus [du Plessis] is a great bloke. He came in and was very warm to all of the boys and everyone liked him from the off. He’s got a lot of insight into Saracens, their mantras and the way they want to play, so he’s been a massive help, trying to help the guys.”

While du Plessis has been selected on the bench, Warriors coach Dave Rennie is happy to go with young gun Fagerson in the department that sets the physicality in any contest.

“He’s got a real point of difference,” Rennie said. “Matt - he’s got great feet. Really explosive - he has the ability to break the line and get in behind the defence to create quick ball. He’s a dynamic defender, he’s deceptively quick, and he’s not a big man but he’s a very good line-out forward.

“Obviously we’ve got Ryan Wilson in there as well, so if we’re using five-man line-outs - he’s very good when we’ve got bigger numbers in. He’s played very well and the decision is made on form,” said Rennie, who completed his triumvirate with Callum Gibbins.

“Ideally you want to pick players with complementary skill sets. If you’ve got three guys that all want to carry and no-one wants to clean any rucks, you’re going to have some problems. What we’ve got with Matt is someone who can give us some go-forward; someone who’s really dynamic.

“In Cully [Gibbins] you’ve got a massive work ethic - really strong defensively post-tackle and really good around the clean-out area. And you’ve got Ryan, who does a bit of both for us - brings a bit of physicality and a really good skill set. He’s a good athlete, really comfortable in the wide channels.

“We think it’s a really good blend of experience. And from a leadership point of view we’ve got a lot of key people on the field. A big chunk of our leadership group are all starting.”