Joe Schmidt has admitted he will fret all the way through Ireland's Test match with Fiji in Dublin after making 13 changes to his starting line-up.
Munster centre Chris Farrell will make his Test debut at the Aviva Stadium on Saturday, with Joey Carbery claiming just his second international start at fly-half.
Head coach Schmidt has rested British and Irish Lions half-backs Conor Murray and Johnny Sexton in a calculated gamble designed to build strength in depth.
— Irish Rugby (@IrishRugby) November 16, 2017
Andrew Porter will make his first international start at tighthead, with Schmidt admitting the 21-year-old faces a real "acid test" in a line-up he accepts will prove a constant "concern".
Asked if he would harbour worries over his decision to field such a changed side, Schmidt replied: "Yeah. We're just hoping that these guys try to follow up the benchmark set in the fine win over South Africa last week.
"It's a real challenge for them. There will be some really tough moments and it will be interesting to see how they work their way through it.
"We want to give them a really stern test now to see if that progression can continue under real stress.
— Irish Rugby (@IrishRugby) November 16, 2017
"It's always a concern (making so many changes), but I can't fault the application of this group.
"If they can bring that into the game, start well and get early confidence, I'd hope they can acquit themselves really well."
Andrew Conway and Devin Toner are the only players retained from last weekend's record 38-3 win over South Africa.
Leinster's Rhys Ruddock will captain Ireland from the back row, following a hugely impressive try-scoring cameo off the bench against the Springboks.
— Leinster Rugby (@leinsterrugby) November 16, 2017
Ireland's starting XV this weekend will boast just 188 caps, further underlining the extent of Schmidt's changes.
"There's no better way to test people than to throw them into the arena," the New Zealander said.
"The only problem with a Test is that you're so visible, and any error is very visible, and you're playing against players who will exploit any weakness."
— Munster Rugby (@Munsterrugby) November 16, 2017
Powerful Leinster front-rower Porter has long since been earmarked to be moulded into a tighthead of some prowess.
The former University College Dublin man remains a work in progress, but Schmidt accepts he faces a baptism of fire this weekend.
"It's the acid test for Andrew, without a doubt," Schmidt said.
"He's got good people around him. He's thoroughly impressed us with his attitude to training.
— Connacht Rugby (@connachtrugby) November 16, 2017
"He's a long-term project for the right here and right now, suddenly.
"And that's what makes him of real interest to us on Saturday.
"Hopefully he can impress and get comfortable in what's going to be a pretty uncomfortable environment."