VIDEO: Ireland stronger now than 2015 World Cup defeat
The 35-year-old seasoned hooker – who will become Ireland's fourth most capped player on Saturday with 106 caps – added that with only five starters on Saturday of the squad that were overwhelmed 20-43 in the 2015 quarterfinal the match had not been a major issue in the leadup to this Test.
"We hope that we've improved our depth and we never get into that situation again," Best said at his eve-of-match press conference.
"If you get injuries to key players that we've brought a lot more players through.
"When you look at the two Six Nations titles that we won going into the 2015 World Cup, we got lucky with injuries.
"Luck plays a big part in that.
"But we didn't have to dig so deep into the squad as we did at the Rugby World Cup."
Best, who captained the British and Irish Lions midweek team on this year's tour of New Zealand, said due to injuries and then players being unavailable for selection head coach Joe Schmidt had had to blood new faces.
"Our hand has been forced in the immediate aftermath of the Six Nations and the summer [June] tour (of Japan and the United States).
"But it's been about giving people an opportunity.
"I feel the squad's in a stronger place now, and that's mainly because people have had opportunities."
Best, who will be playing just his fourth match this term due to injury delaying his return, says that the Ireland camp is an unforgiving environment if you don't keep up.
"The most impressive thing now is the way we've tried to create an environment where if you don't keep up we won't drag you along, you get left behind and then we cut you loose," said the Ulster stalwart.
Best says 21-year-old lock James Ryan is reflective of this new talent coming through as he will make his first start in what is his fourth Test appearance.
Best, though, added Ryan – who has just five matches under his belt for his province Leinster – will have to make his physical presence felt and not go into hiding.
"He just has a presence and hopefully we'll see that tomorrow [Saturday]," said Best.
"The hardest thing is just to go out and impose your game on the opposition.
"You're born with that physical presence but it's making sure we get the most out of that.
"There's no point being this big, physical character if you go into your shell.
"We've seen bits of it and the fact he captained the Ireland Under-20s shows he's a big character and it's important we get that out of him.
"It mustn't just be he fits in, it's he must fit in, but add something as well."