Simon Easterby was revered as a player for his application to his role as a blindside and for his threshold to withstand pain. The Scarlets have lost their last two in the Pro12 League. He will be hurting as a coach.
"Simon was a bloody good professional. I know he will be ticking every single box to make sure the result is a different result this weekend," said Guy. "He will be doing everything in his power, doing all the hours that Joe (Schmidt) does, I imagine, which is a lot of hours, trying his absolute best.
"He did it as a player. He made sure he got every single part of his job correct. The remit is a lot bigger because he's the coach."
The Scarlets went into last weekend as second to Ulster in the Pro12 League. They came out of it with a hiding from the Northern Province and a drop to fifth.
Common sense dictates that the motivation in Belfast would have been, at least, as great as it will be in Dublin given that they are already out of the Heineken Cup.
Will they simply fold on Saturday? "They are too proud a club. If you look across the quality of their team, they've got some real top quality players you would expect to be involved in the Lions at the end of the year. What comes with that, I guess, is a belief in your ability and the desire to make sure you don't perform like that week-in, week-out.
"They have come off two bad defeats in terms of the scoreline. Therefore, it is probably quite a difficult time to play them. They won't want to come here and perform anything below 100pc."
There is more than a whiff of a return to the magic kingdom for inspiration about Leinster's decision to spend the first two days of the week in Enfield, the place where Declan Kidney generated the momentum to take Ireland to their first Grand Slam in 68 years back in 2009.
"Maybe that is the perception of the players that that is why we are doing it. That is not a bad thing either, not that they need their minds focused any more," said Easterby. "It is good to go down there to go through the game plan. Joe and the coaching staff have fantastic clarity of the message, while understanding the magnitude of the game.
"We've got to get the win. If it is a one per cent help, then it will have been a worthwhile trip," he stated.
The main difference between that and this is Ireland were about to embark on the beginning of the build-up into the start of their Six Nations campaign.
Leinster are two-thirds the way through the pool phase of what could be the beginning of the end of their Heineken Cup domination. They need favours all around Europe to gain unsafe passage through to the quarter-finals.
The mantra is to 'live in the moment'. The here and now is all that matters. Leinster can only beat up on the Scarlets for five points and see how that pans out by Sunday evening.