Dublin - Ireland head coach Andy Farrell said Tuesday he had selected "a hell of a team" for the Six Nations opener against Scotland after opting for Conor Murray over John Cooney at scrumhalf.
Register your interest for the British & Irish Lions tickets in South Africa 2021
The choice between the experience of Murray and the outstanding form of Cooney was the biggest call facing Farrell for what will be his first match in charge of Ireland since succeeding Joe Schmidt.
Farrell has opted to show faith in 78-cap Munster player Murray, with the 29-year-old Cooney among the replacements, despite a series of fine displays for Ulster.
Uncapped Caelan Doris, a former Ireland Under-20s captain, has been rewarded with a start at No 8.
"We've got a very competitive squad and the lads have been in great form so it's always going to be difficult," Farrell told the Irish Rugby Football Union website.
"You've got to make a decision and we've got a hell of a team going into Scotland," the English former dual code international added after naming his side from Ireland's pre-tournament training camp in Portugal.
Turning to his choice at scrumhalf, Farrell said: "It's unbelievably tough because Luke McGrath misses out and he's been playing really, really well.
"Conor's been great in and around the group and his training. His calmness has been great for the group and he's in good form as well, he's raring to go," added Farrell, the father of England captain Owen.
"John, everyone knows what type of form he is in. He's had a few protocols this week as far as his HIA (head injury assessment) is concerned but he's got a couple of sessions under his belt and he's ready to go as well.
"They're in a great place, all three of them, and we'd be happy with all three of them being in the squad but unfortunately, somebody has got to miss out."
New skipper Johnny Sexton will lead Ireland at Lansdowne Road on Saturday, starting at flyhalf after overcoming a knee problem suffered in December.
Rob Herring takes over at hooker in place of retired former captain Rory Best.
This will be Ireland's first match since former assistant coach Farrell was promoted from within the set-up after Schmidt's time in charge ended with the crushing disappointment of a World Cup quarter-final thrashing by his native New Zealand.
That defeat for the 2018 Grand Slam winners came soon after a shock pool-stage loss to tournament hosts Japan.
Scotland are due to announce their team on Thursday.
15 Jordan Larmour, 14 Andrew Conway, 13 Garry Ringrose, 12 Bundee Aki, 11 Jacob Stockdale, 10 Johnny Sexton (captain), 9 Conor Murray, 8 Caelan Doris, 7 Josh van der Flier, 6 CJ Stander, 5 James Ryan, 4 Iain Henderson, 3 Tadhg Furlong, 2 Rob Herring, 1 Cian Healy
Subtitutes: Ronan Kelleher, Dave Kilcoyne, Andrew Porter, Devin Toner, Peter O'Mahony, John Cooney, Ross Byrne, Robbie Henshaw