Wales have the bragging rights in Britain now. After qualifying for the last 16 as group winners at the expense of neighbours England, the Dragons have won the first clash between two British teams in the knockout stages of a major tournament.
This was the biggest fixture for both sides in recent memory and it showed. The debutants played out a cagey opening half.
Wales, so often the underdogs, did not seem comfortable with their new favourites tag. While they prefer to play on the counter-attack, they were expected to push the pace against a Northern Ireland side that were content to sit deep.
Wales were passing sideways more than they were forwards, and had to resort to long balls played into the back of the Northern Ireland defence. Northern Ireland were banking on set-pieces to get their breakthrough, but could not make the most out of their corners and free kicks.
The pattern of the game continued in the second half, and a 75th-minute own goal summed up the untidy contest at the Parc des Princes in Paris.
At least the assist was of the highest quality. Wales midfielder Aaron Ramsey passed the ball to Gareth Bale on the left flank. The Real Madrid star fizzed a low cross into the six-yard box, and Gareth McAuley put the ball into his own net from four yards out.
It might not have been a classic, but it would be hard to take anything away from Wales or Northern Ireland, who had the better half-chances and more shots on target (3-1). Both have punched above their weight.
Northern Ireland may be out, but they can hold their heads up high. Wales can continue their historic run. They have booked their place in Lille, where either Hungary or Belgium await.
-In the 19th minute, Sam Vokes nodded the ball on for Ramsey, whose outstretched leg poked the ball home. But the linesman's flag was up for offside. It was the correct call.
- Three minutes later, Jamie Ward's shot from outside the box was tipped over the bar by Wayne Hennessey. Nothing came out of the resulting corner.
- In the 53rd minute, Ramsey's long ball into the box for Vokes was headed wide by the forward. Vokes had a free header from 15 yards out and needed to at least hit the target.
- In the 57th minute, Bale was caught by Oliver Norwood. Bale took the free kick that was just over 25 yards out, forcing Michael McGovern into a save.
- In the 75th minute, Bale's low cross from the left flank was diverted into his own net by McAuley. The defender had little choice but intervene as substitute Hal Robson-Kanu was behind him and ready to tap the ball in.
The talking point
Can Northern Ireland hang on to their manager and build on their recent success?
Michael O'Neill signed a new four-year contract with the Irish Football Association in March, but his achievements in Euro qualifying and at the continental showpiece have raised his stock. Northern Ireland were the first team seeded fifth to top a qualifying group, and they made the knockout stages in France against the odds.
O'Neill is being tipped to be a manager in the Premier League in the near future, and it is understood that there is a £750,000 (S$1.39 million) compensation clause in his contract.
Yet the 46-year-old could help write another chapter in Northern Ireland's football history. They have not featured at a World Cup since 1986, and begin their 2018 qualifiers away to the Czech Republic in September.
In a group that also includes world champions Germany, Northern Ireland will again be underdogs to qualify, even if the runners-up can progress to the play-off. But they have proved the doubters wrong before.
Man of the Match
Bale. He did not get on the scoresheet for a fourth consecutive game, but he made the difference yet again. The Northern Ireland defenders barely gave him any breathing room all day, with at least two men closing him down when he had the ball. But he found room in the 75th minute, and his direct run and cross created the winner.
What the result means
Wales will next face either Hungary, the surprise Group F winners, or Belgium, the world No. 2 side for a place in the semi-finals. They will have an extra day's rest over their opponents.
There have been three own goals so far at Euro 2016 - the same number scored by the top marksmen (Bale and Spain's Alvaro Morata). Iceland's Birkir Mar Saevarsson and Republic of Ireland's Ciaran Clark netted own goals against Hungary and Sweden respectively.
What they said
Wales manager Chris Coleman: "They were better than us at many moments but we showed a lot of heart and courage. These boys never give in, they hang in there, although it wasn't pretty. I'd rather be standing here in the quarter finals than going home having played better. Credit to Northern Ireland, they were the better team here."
Northern Ireland captain Steven Davis: "We'll take a lot from this experience. The fans have enjoyed the journey as much as us and everyone's sad to see it end today."