The Swansea-based region have endured a miserable start to their European campaign with losses to Leinster and Northampton Saints.
No side has reached the knockout stages after losing twice in the opening two rounds by Tandy has challenged his side to achieve the insurmountable.
The Ospreys face Castres Olympique in back-to-back matches in December, beginning at Stade Pierre Antoine
“No-one has ever qualified from losing their first two games, but we will be preparing for Castres in December as if we are still involved,” said Tandy.
“We need to pick up points and wins.
“In this tournament, it is unforgiving. If you don’t take your opportunities or get the bounce of the ball, then it does get difficult.”
Tandy was bitterly disappointed as the Ospreys lost at Franklin’s Gardens but he found solace in their fighting spirit.
“We had opportunities at Northampton, but didn’t quite take them,” added Tandy.
“The squad showed their true character. We could quite easily have folded and let the tournament go, but it is a group that fights.
“When people put them down, they keep fighting.
“We were down 17-6 at half time, and when we got back to 17-13, I really did think we were going to turn the corner.
“We were building momentum, but we conceded a sloppy try.
“We gave away too many turnovers. In the first 20 minutes I think it was seven, and 88% of our possession in the first half was turned over by us.
“The margins are so fine in this sort of tournament and we went from one end of the field to conceding a soft try at the other when I did feel we were starting to get ascendancy over Northampton.”
