Wales overcame a spirited Ireland side reduced to 14 men for most of the match as they launched their 2021 Six Nations campaign with a 21-16 win in Cardiff on Sunday:
AFP Sport looks at three key aspects from the match:
O'Mahony red a sign of the times
Ireland's Peter O'Mahony could have few complaints when he was sent off for elbowing the head of opposition prop Tomas Francis.
Officials are under orders to clamp down on contact above the shoulder at a time when everyone within rugby union is increasingly aware of the concussion-related damage that can be done by head injuries.
It was no surprise when the blindside flanker was shown a red card by experienced referee Wayne Barnes on the 14th minute.
O'Mahony was the first Ireland player to be sent off in a Six Nations match, although Willie Duggan saw red against Wales in the Five Nations in 1977.
Some pundits have called for a rugby league style report system, which spares players from being sent off for such incidents in order to be disciplined at a later date.
But former Ireland No. 8 Jamie Heaslip, commentating on the match for the BBC, said: "It's a head shot. It's reckless and he (O'Mahony) is not in control.
"We are trying to look after players and there is only one option for the referee."
Down a man
Having a player sent off in any standard of rugby is a handicap, but in an international match it usually guarantees defeat.
Ireland had to play more than an hour of the tense encounter a man down after O'Mahony was dismissed and it was hugely to their credit that they led 13-6 at half-time.
But the problems caused by missing a player usually show up in defence and so it proved when George North ran in Wales' opening try in the 49th minute.
Rees-Zammit takes his chance
Wales have plenty of competition for a place on the wing -- both Liam Williams and Josh Adams were in contention for selection until their respective suspensions.
But coach Wayne Pivac insisted Louis Rees-Zammit was "always starting" and it was easy to see why when Gloucester's 20-year-old made the most of a rare opportunity by acrobatically diving for the corner to score a 59th-minute try while airborne.