Joe Schmidt is gearing up for a "horrible couple of days" thrashing out Ireland's World Cup squad selection.
Ireland edged out Wales 22-17 in Cardiff to hit back from last weekend's 57-15 humbling in England, with Jacob Stockdale grabbing a try brace.
Ireland will submit their 31-man World Cup squad to World Rugby on Monday, but will not publicise that final Japanese travelling party until September 8.
Will Addison fared well at full-back but Schmidt branded the Ulster utility back "underdone", suggesting he could miss out amid the head coach's final selection deliberations, with Andrew Conway having furthered his claims.
Asked how close he is to his final 31-man selection, Schmidt said: "I can tell you now, I'm not sure. We need to see what our balance is.
"Whatever you do there's always a risk you don't quite get it right. I don't think we got it right last time (in 2015).
"It's a horrible couple of days. For those players who miss out it's going to be a real body blow, I'm incredibly conscious of that.
"But you can only take 31 players and that's the reality of it."
Jack Carty surely assured himself Ireland's third fly-half berth with an accomplished performance at 10 at the Principality Stadium.
Schmidt insisted that Johnny Sexton will feature against Wales in Dublin next weekend, and that Joey Carbery will beat his ankle injury in time for Ireland's World Cup opener against Scotland on September 22.
Munster playmaker Carbery can offer emergency cover at scrum-half, with Conor Murray and Kieran Marmion likely to be Ireland's two recognised nines in the eventual squad.
Tadhg Beirne should fill the fourth lock berth, with his ability to feature at flanker allowing Ireland to select five back-rowers.
Rory Best showed up well off the bench in Cardiff, making 12 tackles in a combative 20-minute cameo – reasserting his credentials as Ireland's World Cup captain.
Addison, Conway, Jordan Larmour and Chris Farrell could now hand Schmidt the biggest deliberations in his backline selections.
"We'll go back and have a look at it, certainly we'll be as forensic as we can in looking back, then discussing it as coaches over the next day and a bit really," said Schmidt.
"We'll get together tomorrow afternoon and evening, then we'll have more time on Monday morning.
"Will (Addison) did some things really well, he took a cut to the head and then got cramp, so we brought him off to protect him from injury.
"He has such a balanced running style, he gets a good look at the pitch running back from full-back, and he's accomplished at kicking and kicking goals as well. So he's a good back-up from that perspective.
"He's underdone, he hasn't had as much rugby as we would have liked, but then versatility is a huge strength for him.
"He's covered the full spectrum of the back three and 13 which is an asset when trying to narrow a squad down.
"So we'll be looking at him and comparing a few other guys, and seeing who best fits the mould."
Schmidt praised Connacht playmaker Carty for his showing in Cardiff, but admitted again selection calls will not be straightforward.
"Jack's done well, but it's apples, oranges and lemons," said Schmidt.
"You've got a number of different 10 options.
"One of them (Sexton) hasn't played yet, but we all know he'll play next week and will go.
"And another (Carbery) played very well for 50 minutes against Italy, and might be on the bench next week but will certainly be back in time for Scotland."