WALES made a winning start to their 2021 Guinness Six Nations campaign as they made Ireland pay for Peter O'Mahony's 14th minute red card to triumph 21-16 at an empty Principality Stadium.

Munster flanker O'Mahony became the first Irishman to be sent off in the Six Nations, following a reckless contact to the head of prop Tomas Francis – but Ireland recovered to lead 13-6 at half-time.

A Tadhg Beirne try and the boot of Johnny Sexton had the hosts reeling, but second half tries by George North and Louis Rees-Zammit, and 11 points from Leigh Halfpenny, sealed home success.

It took just five minutes for fullback Halfpenny to kick Wales’ first points with an accurate low strike, after Ireland’s Peter O’Mahony was penalised at a breakdown by referee Wayne Barnes.

A few minutes later, however, flanker Dan Lydiate’s return to the side came to a premature half when he sustained a knee injury after twisting in the turf, and was replaced by Josh Navidi.

Ireland received an even bigger blow, though, when Wayne Barnes, after discussion with the TMO, had no option there but to show Peter O’Mahony a red card - with just 14 minutes on the clock.

O’Mahony, with a big run-up, recklessly flew into a ruck, leading with his shoulder, and contacted prop Tomas Francis’ head, and there was little doubt that it was serious and clear foul play.

Looking to capitalise, fullback Halfpenny took his chance to double the lead with another simple penalty kick between the posts, after a high tackle from Johnny Sexton with Wales probing.

Despite being a man down, Ireland still had a good amount of possession, and skipper Sexton halved the deficit with a penalty from out on the left, after replacement Navidi had gone off his feet.

Indeed, 14-man Ireland were adjusting well, and Sexton duly levelled the scores when a penalty was awarded just inside the 22, after centre North had gone off his feet, trying to get a turnover.

Then, within a minute, a huge kick by James Lowe found touch on Ireland’s left wing, Wales made a mess of the resulting lineout, and Robbie Henshaw burst into the 22, ghosting past the defence.

He offloaded to Josh Van der Flier, who nearly got over the line - but was just held up, before Tadhg Beirne took the ball to score the first try, with Sexton adding the extras for a 6-13 interval lead.

Wales responded eight minutes after the restart as Ireland dropped the ball in trying to run it out from their 22, and Navidi released North, who dummied and darted over for an unconverted try.

Pressure on the Irish line from an attacking line-out then resulted in Louis Rees-Zammit sprinting to the corner and diving full-length to touch the ball down one-handed - and Halfpenny converted.

Wales were back on top, and when Alun Wyn Jones charged forward from an attacking line-out, Beirne was penalised for coming in at the side, and Halfpenny gave Wales daylight at 21-13.

Sexton took a blow to the head on Justin Tipuric’s knee, and was taken off for an HIA – but Ireland then got back to within a single score, when Billy Burns struck a penalty from inside the 22.

There was late drama when replacement scrum half Gareth Davies kicked the ball away with 10 seconds left, and Ireland kicked for touch, won the lineout and moved through the phases.

On winning another penalty, however, Billy Burns inexplicably kicked it dead – which meant a fourth win for Wayne Pivac in 11 competitive Wales matches, and a first against a leading nation.

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 (capt), Dan Lydiate, Justin Tipuric, Taulupe Faletau. Replacements: 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 (capt), Conor Murray; Cian Healy, Rob Herring, Andrew Porter, Tadhg Beirne, James Ryan, Peter O’Mahony, Josh van der Flier, CJ Stander. Replacements: Ronan Kelleher, Dave Kilcoyne, Tadhg Furlong, Iain Henderson, Will Connors, Jamison Gibson Park, Billy Burns, Jordan Larmour.

OFFICIALS: Referee: Wayne Barnes (England). Touch judges: Luke Pearce (England) & Alex Ruiz (France). TMO: Tom Foley (England).

Man of the Match: Wyn Jones (Wales).