"It's not an easy moment for the team psychologically speaking," Blaszczykowski, who has appeared 100 times for his country, told reporters on Wednesday.
"But life goes on and the match tomorrow will be of great significance, particularly from a mental perspective. We need to show that we never give up as a team."
Poland have been one of the biggest disappointments of this World Cup, two years after reaching the quarter-finals of Euro 2016 where they went out on penalties to eventual champions Portugal and after finishing top of their qualifying group for the World Cup in Russia.
But an opening day 2-1 defeat to Senegal was followed by a 3-0 drubbing by Colombia, dumping Poland out of the tournament after two games.
For the Poles, only pride is at stake in Thursday's final Group H match in Volgograd against a confident Japan side who need a point to advance into the knockout phase.
"We are where we are and we know that we have failed the Polish football fans and ourselves," coach Adam Nawalka said. "There are no what-ifs."
He said he was not surprised by Japan's form in Russia, which has taken many football fans by surprise, saying several Japanese squad members played for leading European teams.
"The Japanese team has been prepared very well from the mentality point of view," Nawalka said.
Blaszczykowski denied reports of a rift between Poland's star striker Robert Lewandowski -- who scored 16 times in the World Cup qualifiers in 10 appearances, but has yet to find the back of the net in Russia -- and other players.
"When the results are negative, when we don't win and there are problems, then you get fake news," he said.
(Reporting by William Schomberg; Editing by Julien Pretot)
