"I think the game we will see on Saturday will be a Lions contest in almost every position. Ireland want the Grand Slam and Wales want the championship - it's a massive match," said Guscott, speaking at the latest HSBC Lions Legends event in Manchester.
"But as well as being a championship decider, it is also about who is putting their hand up to get a Lions Test spot. Every single position has competition and everyone will be thinking about the Lions - you simply can't help it."
Guscott believes the game will be determined by who gets the better of the back row battles and he has been mightily impressed by the new look Irish combination of Stephen Ferris, Jamie Heaslip and David Wallace to date this season.
"I love the forwards and, for me, rugby is about the back row. You are involved in the game everywhere - you have to attack, defend, tackle and score tries.
"The combination of Ferris, Heaslip and Wallace has been outstanding for Ireland this championship. And the battle between David Wallace and Martyn Williams is going to be a fierce.
"I think Heaslip has been a bit like Tom Croft. He has been awesome - a proper athlete and quick with it.
"Wales skipper Ryan Jones has been talked down as a captain and as a player, but leading his side out at home to win a championship will give him the chance to prove a few things."
If Guscott appears to be leaning towards an Irish win, fellow 1997 Lions tourist Scott Quinnell sees it differently.
"I'm confident Wales are going to win, although I think we've left ourselves too much to do possibly to win the championship. I think the Irish will win the title and we will win the Triple Crown," said Quinnell.
"That means there will be a lot of people smiling around the city of Cardiff on Saturday night. The 2005 Welsh Grand Slam was backed up in 2006 by a win and a draw, so to back up the 2008 Grand Slam with a Triple Crown and possibly a championship would speak volumes for this Welsh side.
"If they can win nine games out of 10 in two years in the Six Nations they will be very much on the right track."