Du Chatinier believes a place in the group stages of the competition will be nothing more than a bonus for his own players, whereas he feels progression is essential for a Celtic side who have already missed out on the Champions League.
Neil Lennon's men boast a 2-0 lead from the first leg at Parkhead last week thanks to goals from Efrain Juarez and Georgios Samaras and hope to finish the job in Holland.
Du Chatinier said: "It's a hard job for us but Celtic have an absolute need to reach to group phase.
"For Utrecht, that means going through is a bonus. The pressure is all on the Scottish team, not on Utrecht.
"They are a very good team on the counter. We know of (Marc-Antoine) Fortune, we know of Samaras, and they will be very quick on the counter-attacks. It's important that we keep them at zero.
"That's our job, as well as to score goals. It will be very difficult against Celtic."
However, he believes he saw enough from the match in Glasgow to have some confidence in overcoming their visitors.
He added: "We saw their weakness - but I won't tell you what it is.
"Maybe tomorrow night after the game I will tell you and it will be no problem."
Asked if Utrecht can still progress despite the two-goal deficit, he pointed to the club's fans to make all the difference on the night.
"Why not?" he said.
"They had the crowd over there in Scotland and we now have the crowd here on our side in Utrecht.
"You have never heard the crowd here in Utrecht when we play at home. It's a little bit similar to what it's like in Scotland.
"Before the game last Sunday, you heard nothing more than 'Celtic, Celtic, Celtic.'
"We know the importance of the game and, after we have had a look at the team in training tonight, we will go to the stadium tomorrow night and see if we can beat Celtic.
"We had two faults for the defenders but we also had two or three chances in Scotland and we know we can also have chances tomorrow night and that we must score.
"It's a difficult job because Celtic lead 2-0 and it will be tough. But why not? I think in the first half we played very well and we saw that back on the DVD.
"Here, at home, we are very strong and we will try to score more goals than their two."
Celtic do not have a good record on the road in Europe and Du Chatinier hopes that is a weak point his players can exploit.
He said: "We are the same, away from home we are not so strong. But at home we are very tough to beat."