Poland head coach Franciszek Smuda admits the pressure of opening the tournament on home soil took its toll on his players.
On Friday, the Poles took the lead against Greece, who were reduced to 10 men in the first half, but were pegged back after the break and were fortunate not to lose after goalkeeper Wojciech Szczesny was sent off and their opponents missed a penalty.
"The pressure for the opening game was really huge because we thought we had to win," said Smuda.
"We didn't want to fail. We want to win but we don't want to lose.
"We know we have one point and because of this we will have a chance until the very end."
On Tuesday night, Poland come up against Russia, who present an entirely different prospect after their 4-1 win over the Czech Republic, and Smuda stressed his players have to focus on their match and not worry about the other encounter in Group A.
"We have to play our well but we have to be more organised in the event that we lose possession," he added.
"We cannot worry about this (the other game). We can only think about our fixture.
"Any result is acceptable for us in this match - except a defeat."
Smuda sidestepped questions about potential friction between rival fans at a match in Warsaw which poses the biggest security challenge of the tournament.
"We try to focus only on the game, only on football," said the Poland coach.
"What happens on the streets - I am not saying it is not our business - but we cannot pay too much attention to that."
Russia coach Dick Advocaat insists he has no concerns about the form of Aleksandr Kerzhakov, who misfired badly in their opening win over the Czech Republic.
The Zenit St Petersburg forward set a new European Championship record with seven shots off target but his replacement Roman Pavlyuchenko scored within nine minutes of coming on.
"I would choose Kerzhakov again. You make choices and you stick with them," said Advocaat.
"I thought he played well, he only forgot to score - which is usually his strong point.
"He worked extremely hard for the team, he was good with the ball and the way he moved was good.
"I do not regret starting with him."
The 29-year-old Kerzhakov shrugged off that performance as Russia look to clinch a place in the knockout stage with victory tomorrow.
"If we keep on winning, I don't care how many goals I score, or if I even score at all," he said.
"It will be a tough encounter because Poland will be at home.
"They drew their opening match against Greece and I am sure they were after a better result, so in order to qualify for the knockout stages, they need to win and will be doing everything to do that."