North’s try and a Leigh Halfpenny three-pointer pushed Wales into an 8-6 half-time lead, after penalties in response from Johnny Sexton and Paddy Jackson.
North, replying to his critics once again, then grabbed a second score after good work upfront from the Welsh maul, Sexton keeping Ireland in the game with a penalty at 15-9.
That six-point gap made for a remarkable final quarter as Ireland threw everything at Wales only to come up short, as a late try from powerhouse centre Jamie Roberts put the seal on the win.
Wales: 15 Leigh Halfpenny, 14 George North, 13 Jonathan Davies, 12 Scott Williams, 11 Liam Williams, 10 Dan Biggar, 9 Rhys Webb, 8 Ross Moriarty, 7 Justin Tipuric, 6 Sam Warburton, 5 Alun Wyn Jones (c), 4 Jake Ball, 3 Tomas Francis, 2 Ken Owens, 1 Rob Evans Replacements: 16 Scott Baldwin, 17 Nicky Smith, 18 Samson Lee, 19 Luke Charteris, 20 Taulupe Faletau, 21 Gareth Davies, 22 Sam Davies, 23 Jamie Roberts
Ireland: 15 Rob Kearney, 14 Keith Earls, 13 Garry Ringrose, 12 Robbie Henshaw, 11 Simon Zebo, 10 Johnny Sexton, 9 Conor Murray, 8 Jamie Heaslip, 7 Sean O’Brien, 6 CJ Stander, 5 Devin Toner, 4 Donnacha Ryan, 3 Tadhg Furlong, 2 Rory Best (c), 1 Jack McGrath Replacements: 16 Niall Scannell, 17 Cian Healy, 18 John Ryan, 19 Iain Henderson, 20 Peter O’Mahony, 21 Kieran Marmion, 22 Paddy Jackson, 23 Tommy Bowe
Date: Friday, March 10 Venue: Principality Stadium, Cardiff Kick-off: 20:00 GMT Referee: Wayne Barnes (England) Assistant Referees: Jérôme Garcès (France), Matthew Carley (England) TMO: Ben Skeen (New Zealand)