Leverkusen host the big-spending Ligue 1 leaders on Tuesday in the first leg of their last 16 clash in Europe's premier club competition.
Hyypia's men sit second in the Bundesliga but are in poor form, having lost five of their last seven competitive matches – including a DFP-Pokal quarter-final exit against second-tier side Kaiserslautern.
The former Liverpool defender saw plenty of positive signs in Saturday's 2-1 home loss to Schalke though, and feels they could spring a surprise, despite admitting PSG were heavy favourites.
"PSG has invested a lot of money," Hyypia said on Monday.
"They are favourites, we are outsiders. But I think we have a chance against them.
"If we play like (we did on) Saturday against Schalke, we can make life very difficult (for PSG). We had so many opportunities."
With eight goals in five group stage matches, PSG's star man is undoubtedly Sweden striker Zlatan Ibrahimovic.
But Hyypia knows the French champions have quality throughout their side.
"We should not focus only on 'Ibra'," he added.
"(But) he is an excellent player, one of the best in the world. Everyone talks about him.
"He can score amazing goals. You can have a perfect match in defence and not prevent him from scoring. But all their players are good."
