Klopp said the game should be about even if each side plays to their highest standard and it could then come down to just the smallest mistake to determine who wins.
Liverpool manager Juergen Klopp has warned his players that they must stop Paris St Germain as the two sides meet on in the French capital on Wednesday.
The 'Reds' head into the game sitting second in their Group C standings, behind leaders Napoli on goal difference, with PSG third on five points and Crvena Zvezda bottom with four - all four teams still have everything to play for.
While addressing the media, Klopp said that his players are "psychologically ready" for a tantalising clash.
"Little mistakes can make the decision, can be decisive," told Klopp.
"I'm not worried, and my team. I'm now together with them for three years and one-and-a-half months, roundabout. And in this time they were always psychologically ready," he added.
PSG faced missing two of their star attackers, Neymar and Kylian Mbappe, who were injured for their weekend 1-0 league win over Toulouse, but coach Thomas Tuchel confirmed they will both play against Liverpool.
"In this group it was from the beginning clear that, it's a difficult one and now that's it and we are here. We never moaned about it, we didn't even think negatively about it," said Klopp.
Red Star Belgrade lie in fourth but are also in contention to qualify from the group after a shock 2-0 win over Liverpool earlier this month.