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Rory Best has tipped rookie lineout caller James Ryan to come of age against the "world's best lock" Alun Wyn Jones in Cardiff.
Wales Captain Jones will equal Gethin Jenkins' record combined Wales and British and Irish Lions caps haul of 134 in Saturday's Guinness Six Nations decider.
The 33-year-old skipper starts the Principality Stadium clash as the master when compared with his Irish counterpart, Leinster's 16-cap, 22-year-old Ryan.
Ireland captain Best however believes Ryan's finest trick in a stunning start to his career has been to fool the Test arena he has been around for what seems an "eternity".
"James is a reasonably young kid but it seems he's been around – with the performances he puts in – for an eternity," said Best of Ryan, who will call Ireland's lineout for the first time in Cardiff.
"He hopefully will take it in his stride, and I think the great thing for us is the depth.
"This will be the third lineout caller of the Six Nations. With Devin Toner injured, we have a lot of options and it is great to see in such a critical area of the game.
Grand Slam on the line.... Packed Principality! Will @WelshRugbyUnion win tomorrow?#WALvIRE #GuinnessSixNations pic.twitter.com/7LjzjGHHZ1 — Guinness Six Nations (@SixNationsRugby) March 15, 2019
"When Paul O'Connell was in there, if he didn't play you'd really struggle to get a lineout caller, then Donnacha Ryan emerged a little bit.
"Now to have guys like Iain Henderson, Quinn Roux and now James all capable of calling a lineout, that is very encouraging."
Jones could help Warren Gatland become the first Wales coach to win three Grand Slams, should the hosts prevail in Cardiff this weekend.
The uncompromising Ospreys second row is as famed for his gritty performances as his glowering demeanour, but Best insisted the Wales skipper's revered leadership begins and ends with his true personality.
"Actually he's not as intense off the pitch as he is on it; he's a great guy," said Best.
"I actually roomed with him quite a few times on the last tour to New Zealand. He and I are maybe a little bit older than most of them. We get on very well and I've known him a long time.
"I think the thing with him is that, there is that picture of all the Welsh huddle looking at him after the game, and there are all sorts of memes, but he gets that respect because he's a really, really good guy.
"There is nothing that you couldn't ask him to do. Even stupid things.
"When you're rooming with him and you come up after a training session or a gym session, he'll have been down and collected the laundry and it's sitting on your bed.
"He's a great guy off the pitch but an absolute handful on it.
"He's a competitive guy. That's what you come to expect and he's probably the world's best lock. It's another of the big challenges which James Ryan is going to come up against."
