Northern Ireland captain Steven Davis and star striker Kyle Lafferty are both left disappointed by the team's display in the opening Euro 2016 defeat by Poland.
Arkadiusz Milik's 51st-minute goal gave the Poles a 1-0 win over Michael O'Neill's in Nice.
"We gave it our all but it wasn't good enough in the end," Davis said. "We defended reasonably well but we need to be better on the ball."
Lafferty said: "Unfortunately we didn't turn up today. Michael will have a word with us. He'll speak the truth. We'll take note of it and I'm sure we'll give a more determined performance against Ukraine on Thursday."
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