Gatland and Ireland boss Farrell have paired up on Lions coaching duties, but will now resume head-to-head battles in Europe’s premier Test competition.
The Cardiff stadium can become deafening for players with the roof closed, as the sound continually reverberates, but world No1-ranked Ireland have no fear.
“We have to agree to the roof being closed,” said Farrell. “We wanted it closed as well, to sample the atmosphere and keep progressing on our journey.
“It’s great, it’s a fantastic stadium. We’ve been there before when the roof’s been closed and there’s no atmosphere like it.”
Gatland attempted to heap the pressure on Ireland this week by suggesting the clash represents a “free shot” for Wales. Farrell rejected the premise, before laying out his expectations for a tight encounter.
“I don’t know about a free shot in Test-match rugby. Where do you get those from?” said Farrell. “There’s no doubt Warren will expect his side to win, and I expect our side to win.”
Wales must do without Leigh Halfpenny, who suffered a back spasm, with Liam Williams stepping in at full-back. Assistant coach Jonathan Humphreys backed Gatland to get the best out of Wales — and quickly.
“Gats has tons of experience, he knows what he wants and he knows how to get coaches working together and on the same page very quickly,” said Humphreys.
“We are really clear about how we want to play and how we want to play against the best in the world right now in Ireland.”