Harry Maguire's header and a stoppage-time penalty save from Andre Onana preserved a 1-0 victory at Old Trafford as United picked up their first points in Group A after beginning the competition with back-to-back losses.
Erik ten Hag's side needed another win over the Danish champions to thrust themselves back into contention for a place in the last 16, but Neestrup insists it won't be easy for them.
"For me, it's not about hope. For me, it's about strong belief that we can get a result," said Neestrup, who felt there was nothing to separate the sides in the first meeting.
"I think the game over 95 minutes was totally equal and I expect the same tomorrow."
The 35-year-old expects Copenhagen to be boosted by the Parken crowd as they try to lift themselves off the foot of the group, having taken just a point after three games.
"What can they expect? I would say with all the respect I felt when I stepped into Old Trafford, then I felt the historical atmosphere," said Neestrup.
"But you can't compare Old Trafford with Parken because the intensity is times 100 in terms of what we played in two weeks ago.
"Then this is a standard (that), for me, is way above Premier League, to be honest."
United striker Rasmus Hojlund will return to his hometown club on Wednesday and could come up against his brothers, Emil and Oscar. The latter came off the bench late on in Manchester.
Copenhagen defender Kevin Diks backed up his coach's belief that the Danes can give United another run for their money.
"I am not saying that we are always favourites against them," he said.
"But we have shown what we can do against them. We will see. But of course, I see us as favourites. It's not about luck."
