Rory Best see Iain Henderson as "a genetic freak" who is only tapping into his potential.
"Hendy's a bit of a genetic freak, and if you give him the ball in certain situations he's very hard to stop," said Best.
The main problem for the 23-year-old is that he can sometimes appear relaxed to the point of horizontal.
"He's very laid back and it's something that, as he's still very young, we're trying to get him to look at, though he's a bit more clued-in.
"It's hard to know where the limit is with his potential," said Best.
"But he's a very chilled out guy, he spends a lot of hours in the day asleep."
Henderson took over Ireland's number four shirt on Saturday and has no intention of handing it back to Devin Toner.
He was the outstanding figure against Canada, especially for the impact in contact he brings.
The Ulsterman is built differently to most other Irishmen. He always has been.
The official statistics reveal a 6'6" tall second row weighing in at 121 kilos (or 19 stones in old money).
Moreover, where the majority of Irish players have had to work on the weight and keep it there, Henderson (pictured) has always been a naturally big man with the feet of a much smaller one.
It is his footwork that enables him to find soft shoulders and his acceleration that makes him a unique threat in open ground.
The 23 year-old offers, in no particular order, explosive physicality in the maul, the ruck, the collision and on the ball.
He turns Ireland's brigade of natural ball carriers from two into three, joining Sean O'Brien and the returning Cian Healy as men who make life easier on those in behind them.