Wales manager Chris Coleman expects to face a resilient Northern Ireland in their Battle of Britain at Euro 2016.
The pair were thrown together for a last 16 tie when the Republic of Ireland pulled off a shock 1-0 victory over Italy to reach the same stage of the competition.
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Robbie Brady's late header changed the dynamics of the second round draw as Turkey, who had been expected to play Group B winners Wales, were eliminated.
Northern Ireland, one of the four best third-placed teams, had been lined up to play against hosts France, but instead will now provide opposition for Wales at the Parc des Princes in Paris on Saturday evening.
Coleman said: "Northern Ireland are more physical than Turkey.
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"They get the ball forward quicker. That's where their strength is.
"They are superbly organised and defensively so difficult to break down.
"They are excellent from set plays."
Coleman said the camp were back in game mode after celebrating the 3-0 victory over Russia, which confirmed them as finishing above England to win their group.
The squad had a barbecue with family and friends in Toulouse before heading back to their Brittany base.
Coleman also said the players ended their booze ban by celebrating victory with a couple of beers after the game.
"It was great as we had not had a beer since we had been in camp," said Coleman.
"Some of the senior players came to me in the dressing room as we had one can of beer each in the dressing room.
"They came to be and said 'can we have one beer back at the hotel? Then we will call it a night as we are playing on Saturday'.
"I didn't have to say 'don't be stupid' or anything. They took care of that.
"Then it was a great atmosphere at the hotel, all the kids were there. We all needed it.
"The chefs did the food. I don't trust any of us! I have done a few BBQs myself in my garden, but I am not sure I could give the type of burgers I dish up to our lads."
The euphoria in the Wales camp after the Russia victory was summed up by Joe Ledley's post-match victory dance.
Ledley's moves after qualification was secured in Bosnia-Herzegovina last October went viral, and the Crystal Palace midfielder showed off another impressive routine in Toulouse.
"I had them in the locker," laughed Ledley.
"Obviously my mates back home know the dance moves and what I'm capable of doing.
"I just needed the occasion and Russia was that.
"I just wanted to enjoy it.
"But I'm not sure what I've got left!"
Ledley was part of the Celtic side which beat Barcelona in the Champions League in 2012 but he admitted the emotion of Wales' win over Russia topped that.
"We beat the best team in the world and Celtic Park was frightening," said Ledley.
"I will never forget that night, but to be with your nation, to have come from where we have, to be here and topping the group, means that little bit more to myself."