Northern Ireland captain Steven Davis has issued a scathing assessment of his side's Euro 2016 debut, claiming that they were "not good enough".
The UK nation fell to a 1-0 defeat against Group C rivals Poland in Nice, failing to register a single shot on target as Arkadiusz Milik struck the game's only goal.
Southampton midfielder Davis told BBC Sport: "We need to be better on the ball and braver - it's a learning curve. We always knew it was going to be difficult but we were not good enough."
Meanwhile, teammate Kyle Lafferty believes that Michael O'Neill's side were simply overcome by the occasion of reaching their first tournament in 30 years.
The Norwich City striker said: "We were overawed. We knew it would be tough, but I think the whole performance was not a Northern Ireland performance and on Thursday we will go and put it right.
"We can change the fight and determination. Michael will talk to us and we will take notice and we will have a more determined and heartful performance on Thursday."
Northern Ireland's second Euro 2016 fixture sees them face Ukraine before wrapping up the group stage with a match against world champions Germany.