Streich's men nailed down a place in the Europa League thanks to a 2-1 win over Greuther Furth on Saturday, while Schalke's home loss to Stuttgart by the same scoreline means the race for fourth place will go down to the wire.
The two protagonists in that lucrative race meet in a winner-takes-all encounter at Freiburg's Mage Solar Stadion next weekend, but Streich is not about to get carried away.
"There are moments in life when the sun is shining, but then the moments of shade are always just around the corner," he said.
Streich has been coy on his side's European hopes throughout their season of over-achievement, but admitted that even he was distacted by the crucial events in Gelsenkirchen on Saturday, which leaves Schalke with a one-point lead over Freiburg.
"The scoreboard kept going ding-dong with the results and I react like any other Pavlovian dog and look in the direction of the noise when I hear it," he said.
While Streich is keeping his emotions in check, the gravity of next week's match is not lost on club president Fritz Keller.
"It's fantastic that we have such a final game in front of our own fans," he said.
"The lads and our fans have deserved it. It's sensational."