The Barcelona forward is Poland's all-time record goal-scorer but will turn 36 in August, and will be almost 38 at the next World Cup in North America in 2026.
However, he appears determined to play on and not bow out after a disappointing tournament in Germany in which Poland were the first team to be eliminated following defeats in their opening two matches.
"Tomorrow is not my last game," Lewandowski told reporters on the eve of Tuesday's match in Dortmund, after saying that an emerging generation of young players had given him "extra energy".
"I will be 36 soon. I still have that fire inside of me and nobody outside can affect my decision. It will just be me and my family," said the striker who made his name at Borussia Dortmund a decade ago.
"One day I will wake up and maybe think it is time to retire but today I feel this team has a future.
"I know things have not worked out before and during this tournament but we were in the group of death.
"It has not been easy but that doesn't mean we can't come back much stronger in the future."
Lewandowski, who has won more than 150 caps, is playing at his fourth European Championship and has also appeared at two World Cups.
He missed Poland's opening game at this year's Euros after suffering a thigh injury in a friendly against Turkey a week before the tournament began.
Absent from the 2-1 loss against the Netherlands, he only appeared as a substitute in their next match, a 3-1 defeat by Austria.
"I wanted to be fully fit so it was tough being unable to help the team on the pitch," he said before declaring himself ready to start against the 2022 World Cup runners-up.
"I am ready to play from the beginning. I think I can cope with playing 90 minutes."
