'We believe we can win' - Michael O'Neill on Northern Ireland's clash with Wales
The game will take place at the Parc des Princes on Saturday evening.
Northern Ireland manager Michael O'Neill said his side got the more favourable side of the draw - lining up against Wales instead of France on Saturday.
It looked for a long while on Wednesday night that Wales would play Turkey and Northern Ireland would tackle hosts France in the last 16.
But the Republic of Ireland's 1-0 victory over Italy - Robbie Brady scoring a late winner in Lille - changed the dynamics of the second-round line-up.
Turkey were eliminated as the Republic reached the next stage, and Group B winners Wales will now play Northern Ireland, one of the four best third-placed teams, at the Parc des Princes in Paris on Saturday.
O'Neill said he believes it will be a "fantastic game".
“We will be heading back to the Parc des Princes which as we know from Tuesday night is a brilliant stadium," he said.
"We will benefit from the familiarity of having been there already, of having done the journey and of having played on the pitch.
“The results tonight put us in what is arguably the more favourable side of the draw, so we are pleased about that.
“We are in no doubt that it is going to be a tough game against Wales but we will go into the match believing that we can win and that we can progress.”
Wales manager Chris Coleman conceded Northern Ireland are "difficult to break down" defensively.
"Northern Ireland are more physical than Turkey," he said.
"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."
England, who play Iceland in the last 16, are in the same half as France, Germany, Italy and Spain.