Not surprisingly, Celtic centre-half Trusty views that visit to Croatia as particularly "huge" for the Glasgow club.
"Every game is huge," he said. "We're confident in ourselves and in our ability. We know the power we possess and it's really is in our hands.
"We can compete with anybody. When we're on it, and playing our game, I think we've shown to you guys, but also to ourselves, that we can play.
"I think we're really confident going into any game, whether it's league or Champions League, so we're in a good spot."
Who would have thought after match-day two, when Celtic suffered a 7-1 humiliation away to Borussia Dortmund, that they would now be undefeated in their last three Champions League games?
To put that into perspective, their last such unbeaten streak was in 2012, spread over two campaigns, and they are unbeaten in five such games at home having lost eight of their previous nine at Celtic Park.
No surprise that Johnston views it as "definitely a step up" from last season, when Celtic finished fourth in their group behind Atletico Madrid, Lazio and Feyenoord in Rodgers' first season back as manager.
"I think we have matured," he said. "I think that just comes with the territory of it being the second year under Brendan now. There's a lot more comfort in the system and in the players. Everyone knows their roles really well.
"Those results we had earlier in the campaign have really given us confidence that, when the going gets tough, we can defend in a block of 4-4-2. We can get through those difficult moments. We can also use this ground to our advantage and play free-flowing, attacking football.
"We don't need to be scared to be who we are. That's something we've definitely shown this year and learned. It's definitely a step up from last year."
With a home game against a Young Boys side who sit bottom of the table without a point before visiting Villa Park, Johnston believes Celtic are in a strong position to at least reach the play-off stage.
Indeed, he praised the side's resilience after recovering from centre-half Cameron Carter-Vickers' own goal to draw with the impressive Belgian champions.
"I think we've shown, especially here at Celtic Park, that we can be a really difficult team to beat, so it's important that we keep that confidence and don't let that rock us," he said. "I think we showed that it didn't really rock us given the way we performed in the second half."
Johnston expects "a difficult atmosphere" in Zagreb against a side one place and one point behind.
"At the same time, we can build on what we've done in previous away matches, like Atalanta, where we can go to these difficult grounds, dig in and hopefully claw out another result. If we do that, we leave ourselves in a really good position," he added.