Iordanescu - who watched his father Anghel coach Romania to the 1994 World Cup quarter-finals in the United States - said his side were focused on staying well-organised and playing with intensity at the Munich Football Arena on Tuesday.
“We know we have to be close to perfection tomorrow to have a good result,” he said. “Mentally we have to be very strong and decisive. We have to show that on the pitch.
“I think my team can do that. We must not make individual mistakes and be very well organised.”
Romania are 40 spots below seventh-placed Netherlands in the FIFA rankings and have won only two of their 19 games at six Euros finals appearances.
But Iordanescu’s side, who topped Group E with four points, made an impressive start to the tournament with a 3-0 win over Ukraine before a 2-0 loss to Belgium and a final draw against Slovakia that made them group winners.
They face a Dutch side that have disappointed so far and finished third in their group after losing 3-2 to Austria but Iordanescu cautioned against reading too much into that performance.
“Don't be fooled by how the Netherlands played against Austria," he said.
“No game is easy, especially not one that can get you into the quarter-finals. The Netherlands are favourites tomorrow. They have incredible players but we have our own strengths."
Those strengths include defensive discipline and team sprit on and off the pitch that have carried Romania through the tournament along with boisterous support from fans at the stadiums.
Iordanescu said he was also considering changes beyond the forced replacement of suspended left back Nicusor Bancu, who misses out due to two yellow cards, adding that whoever plays knows what is at stake.
"Reaching the quarter-finals would be fabulous," he said. "It's hard to put into words. It's important that we're strong, disciplined, organised and decisive, then there could be things that go in our favour."