Peter O'Mahony was sent off as Wales held off a spirited 14-man Ireland side to start the 2021 Six Nations with a hard-fought win.
Wales took advantage of Peter O'Mahony's early dismissal and survived a fightback from 14-man Ireland to start their Six Nations campaign with a 21-16 win in Cardiff.
O'Mahony was sent off in the opening 15 minutes for contact to the head but Andy Farrell's men overcame their disadvantage in personnel to lead 13-6 at the interval.
But tries from George North and Louis Rees-Zammit turned the contest back in Wales' favour, with Ireland unable to produce another riposte.
The visitors were also dealt a late blow as Johnny Sexton went off with a head injury, giving Farrell plenty to worry about ahead of next week's clash with France.
Ireland were pinned for side entry at the ruck in the opening five minutes, giving Leigh Halfpenny the chance to boot Wales into a three-point lead.
O'Mahony was guilty of a much more serious infraction in the 14th minute, the flanker seeing red for leading with the elbow to the head of Tomas Francis as he attempted a clearout.
Wales, who earlier lost Dan Lydiate to a leg injury, doubled their advantage four minutes later through Halfpenny's trusty right peg.
However, Ireland enjoyed the majority of possession and territory thereafter in the first half and were rewarded for an extremely spirited fightback.
A pair of Sexton penalties drew Ireland level and a break from Robbie Henshaw then enabled Tadhg Beirne to dive over and give them a seven-point lead to defend.
Wales saw scrum-half Tomos Williams suffer a hamstring injury on the stroke of half-time but his absence did not prevent the hosts from getting back into the contest.
O'Mahony leaves Ireland wondering what might have been
The officials have placed an emphasis on cutting out contact to the head and O'Mahony's moment of indiscipline was ultimately decisive.
Ireland's response to going a man down and their spirit in trying to win it in the additional minutes indicated they perhaps would have emerged victorious with a full complement of players.
North & Rees-Zammit right the ship
It was those on the right edge for Wales who put the hosts back in command. North's try was his 42nd in 99 matches for his country while it is now two in five for his team-mate on the wing.
Rees-Zammit showed remarkable acceleration to find the corner after Wales worked the ball quickly through hands and then had the body control to avoid hitting the corner flag before dotting down.
What's next?
Wales are in Edinburgh to tackle Calcutta Cup winners Scotland at Murrayfield. Ireland welcome a France team fresh off a demolition of Italy to Dublin.
North capitalised after a series of Ireland handling errors to surge through a gap on the right and touch down, but Halfpenny misjudged the conversion attempt.
But that instance of profligacy from the tee did not prove costly as Rees-Zammit produced a stunning finish in the right-hand corner to put Wales back in front.
Halfpenny atoned for his earlier miss with a superb kick from the sideline to add the extras before knocking over a more routine kick as a penalty made it 21-13.
Billy Burns trimmed the deficit back to five points shortly after Sexton's exit but he failed to find touch with a penalty as he attempted to push Ireland to the five-metre line in stoppage time as Wales survived a dramatic final push from the visitors.
