For Neil Lennon's Bhoys, it's simply Champions League or bust when they go toe-to-toe with Shakhter Karagandy in Kazakhstan.
A spot in the Europa League awaits the loser of the ties, which kick off tonight in Astana and are completed at Parkhead a week tomorrow.
But that would be no consolation for Celtic.
Income from the Europa League is worth just 12% of what can be earned in the Champions League.
More importantly for Brown and his team-mates, the Champions League is where they all want to test themselves against the world's best players.
So, the prospect of stumbling at this final stage, having safely negotiated two qualifying rounds against Cliftonville and Elfsborg, simply isn't an option.
Brown concedes, however, that only their very best will be good enough to book Celtic that coveted place.
He said: "The Europa League would be no consolation.
"Though it is a good thing to have in the background, everyone here wants the Champions League.
"It's the best competition in the world, and so getting Shakhter back to Celtic Park for the second leg next week is huge for us."
Celtic made a staggering £22.4 million from their run to the Last 16 of the Champions League last season.
Just booking their spot in the Group Stage would guarantee at least £15m, which would give a massive boost to Lennon's spending budget in the final days of the transfer window.
Getting in the group stage would also make moving to Parkhead more attractive to potential signing targets.
Lennon is still working hard to try and bring Teemu Pukki to Parkhead, but has other options which they are working on behind the scenes.
Brown is not prepared to indulge in thinking that far ahead, and is focused fully on getting the club over this hurdle.
He said of adding more players: "That's not for me to say. It's whatever the gaffer and Peter Lawwell think is best for the club.
"The players we have got can definitely do a job."
That's been proven by the results they have already achieved since the campaign kicked off in Belfast on July 17.
"It's been a long season so far," joked brown. "But, it's what we have to do to get into through.
"The gaffer began the preparation for this back in March. He is always thinking ahead, and I'm sure he will be thinking about next pre-season.
"We will also know what we are doing after Christmas. He is really good that way, and it pays off."