Wales 21-16 Ireland, Principality Stadium
The result means Wales finish the opening round of the tournament positioned second in the table that is topped by France while Ireland are placed fourth. This was also Wales' fourth win from 11 matches under head coach Wayne Pivac.
Wasps were the first to get the the points on the board with Leigh Halfpenny kicking a penalty goal in the fifth minute but moments later they suffered their first injury blow with Dan Lydiate leaving the field.
Ireland were dealt a serious blow in the 13th minute when Peter O'Mahony became the first Irish player to be sent-off in the Six Nations for making contact with the head of Wales prop Francis at the breakdown.
With Johnny Sexton penalised for a high tackle, Wales got another opportunity for a penalty kick which Halfpenny managed to get it across to take the home side to a 6-0 lead. The 24th minute saw Wales centre Williams and Ireland lock James Ryan leave the field with head injuries.
Despite being down by a player, Ireland dominated the second quarter with Sexton kicking penalties on the 28th and 35th minutes to level the scores before they got their opening try when Robbie Henshaw offloaded to Josh van der Flier, who in turn sent lock Tadhg Beirne over the line. Sexton's conversion meant Ireland had a 13-6 lead at the end of the opening half.
Wales showed better intent at the start of the second half capitalising on an Irish hour with George North dotting down to narrow down the gap to two points after Halfpenny missed out on the conversion.
Pivac's men reclaimed the lead at the end of the third quarter when Louis Rees-Zammit finished in the right corner with Halfpenny kicking a conversion and followed it with a penalty goal in the 65th minute making it 21-13.
Billy Burns replaced Sexton, who left the field for a HIA in the 70th minute kicked a penalty goal in the 72nd minute to bring their deficit down to five points. Andy Farrell's men though were relentless despite the numerical disadvantage but a couple of errors combined with stern defence from Wales stopped them from getting over the Wales' tally.
Wales: Leigh Halfpenny; Louis Rees-Zammit, George North, Johnny Williams, Hallam Amos; Dan Biggar, Tomos Williams; Wyn Jones, Ken Owens, Tomas Francis, Adam Beard, Alun Wyn Jones, Dan Lydiate, Justin Tipuric, Taulupe Faletau.
Reserves: Elliot Dee, Rhodri Jones, Leon Brown, Will Rowlands, Josh Navidi, Gareth Davies, Callum Sheedy, Nick Tompkins.
Ireland: Hugo Keenan; Keith Earls, Garry Ringrose, Robbie Henshaw, James Lowe; Johnny Sexton, Conor Murray; Cian Healy, Rob Herring, Andrew Porter, Tadhg Beirne, James Ryan, Peter O'Mahony, Josh van der Flier, CJ Stander.
Reserves: Ronan Kelleher, Dave Kilcoyne, Tadhg Furlong, Iain Henderson, Will Connors, Jamison Gibson Park, Billy Burns, Jordan Larmour.