Czech Republic captain Tomas Rosicky has returned to Prague for treatment on an Achilles problem that has left him doubtful for the quarter-final clash with Portugal.
He has been undergoing intensive treatment on the injury.
Rosicky is set to rejoin the squad in Wroclaw on Tuesday but remains a major doubt for Thursday's match in Warsaw.
After the win over Poland, Czech coach Michal Bilek said: "It's difficult to say [whether] we have Rosicky. He's irreplaceable.
"He tried [the injury] before the match and he couldn't start, but Daniel Kolar played a great match."
Bilek was impressed by the improvement his young team made after a first half in which they were second best to Poland.
"We started improving at the end of the first half but during the break I told the players to be patient and to be careful at the back," Bilek added.
"We were patient and we were able to counter attack because they opened the defence."
Midfielder Petr Jiracek scored the decisive goal 18 minutes from time to send the Czechs through and in doing so end Poland's Euro 2012 dream.
The Wolfsburg player said his side had topped Group A because they had made a gradual improvement as the match wore on.
"We had a poor start but we gradually improved, started to create chances and finally, we deserved to score," Jiracek said.
"I'm very happy that after the first match, when we didn't do very well, we were under pressure but won our remaining matches and we showed everybody that we're worth it.
Czech goalkeeper Petr Cech admitted the occasion had got to the team but that their recovery had shown character.
"We started badly and let the occasion get to us a little bit, the home side capitalised on our mistakes," Cech, the Chelsea player, said.
"But with time we got better, we created chances and then scored a deserved goal."
A Greece goal just before half-time in Warsaw, where Group A's other game was taking place, meant Czech Republic needed to score to avoid elimination from the tournament.
"We knew the result (of the other game). They told us and we could see it on a screen, but we focused on ourselves, decided not to wait for miracles and to score instead."