Brisbane's feint hopes of qualification 16 hinge on beating Urawa by several goals, while also hoping that Suwon Bluewings defeat Beijing Guoan in the other Group G clash to be played simultaneously.
With a goal difference deficit of four to be made up, Thijssen knows what Roar has to do.
"For us it's very clear," Thijssen said.
"We have to score a couple of goals and of course that's not easy.
"That's the only (way) we can reach the next (stage).
"We have to play attacking football without losing the organisation - that's very important of course."
That task will be made much simpler after marquee man Thomas Broich was passed fit to face Urawa.
Broich copped a hit to his face in Friday night's 2-1 elimination final loss to Adelaide United but has trained strongly in the lead-up to the clash at the Gold Coast's cBus Super Stadium.
Midfielder Luke Brattan is adamant nothing will change for Roar in light of its need of goals.
"That's just how we play in general," he said.
"We're a very aggressive team, very attacking and we've got great attacking players, very creative players, and we'll still look to score a lot of goals."
Brattan admitted the season would feel like a waste if it can't make the ACL round of 16.
"We're used to winning," he said.
"You look over the last five years and we've won three out of five (A-League titles).
"We haven't been past the group stages of the Asian Champions League yet so that's definitely a goal."
Currently undefeated in the J.League, Urawa will be playing for pride alone as it cannot progress to the tournament's next stage.
It beat second-placed Gamba Osaka on the weekend but has left several key players behind in Japan.
