Frank De Boer hopes the tiny percentage of Ajax fans he describes as ``crazy'' do not disrupt Wednesday night's Champions League clash with Celtic at the Amsterdam ArenA.
UEFA opened disciplinary proceedings against the Dutch club after some of their supporters clashed with police and stewards during the Group H game at Parkhead last month which the home side won 2-1.
Evidence of damage to seats in the away section of Celtic Park also came to light after ``instances of disorder'' were dealt with by police in Glasgow ahead of the match.
The case will be dealt with by UEFA's control and disciplinary panel on November 21.
Speaking on Tuesday at the pre-match media conference at the Ajax stadium, the Dutch coach praised his side's supporters for the way they backed their team at Parkhead, saying, ``there were moments when they made more noise than the Celtic fans did which was fantastic''.
However, De Boer admitted that some Ajax fans remain a concern when asked if he was confident of the game passing off trouble-free.
``I am confident in that but you never know,'' said the former Rangers player.
``There is always some crazy people (who) try to disturb something but hopefully it will not happen.
``There have not been so many incidents like that over the last couple of years.
``Of course, it was a bad thing they did in Glasgow and hopefully they will be punished for that but normally 99 per cent are good supporters.''
The Dutch champions are bottom of Group H with one point from three games, two behind third-placed Celtic and four behind AC Milan with Barcelona topping the section with seven points.
De Boer is aware of the importance of the game against the Scottish champions - victory is needed if they are to have a realistic chance of playing European football in the new year - and he said: ``We think we will succeed tomorrow if we play the same as we did in Glasgow.
``It is a crucial game for us. For them, a draw is maybe enough so they can wait more than they did in Glasgow.
``We have to force the game but we are in good shape to create chances and get the three points.''
Neil Lennon claims Celtic will have to be at their best against an Ajax side he believes are as good as AC Milan and Barcelona.
A victory over Ajax could take the Scottish champions ahead of Milan, depending on how the Italian side fare against leaders Barca ,and set up a glory night at Celtic Park when the Rossoneri visit Glasgow later in the month.
However, the Celtic boss, who expects Georgios Samaras, Kris Commons and Mikael Lustig to be fit, tried to dampen down those expectations.
``We always knew that the double-header against Ajax would be pivotal and it has proved to be the case,'' he said.
``You don't know what is round the corner but what I would say is that on their day Ajax are as good as Barcelona and Milan.
``They caused us as many problems as both those teams and I think it will be the same tomorrow night.
``I think it was important that we got some points on the board against Ajax. But we are under no illusions as to how difficult this will be.''