Ajax dropped to the Europa League after finish third in the Champions League group stages and they had to face a Getafe side in the knockout stages, which was also not easy.
The Dutch champions needed their fans and they did show up, but were unruly.
Ajax has now been fined by UEFA over crowd trouble.
Getafe striker Deyverson was hit by a lighter thrown from the stands after opening the scoring, while fans also damaged seats at the Coliseum Alfonso Perez.
UEFA has imposed a fine of almost £50,000 but opted against activating a suspended one-match ban on traveling supporters, the club announced in a statement.
A statement on ajax.nl read: "Ajax has received fines from UEFA for misbehavior during last month's games against Getafe.
"The European Football Association has imposed a penalty for the destruction of chairs and the throwing of objects with a total amount of 53,250 euros. The responsible parties have been identified, Ajax is starting the procedure to recover the sanctions from them.
"As a result of disturbances and vandalism in October last year during the match with Valencia in the Champions League, Ajax still had a suspended sentence of one match without visiting supporters. This measure is not being imposed now but will remain in force."
Ajax was previously fined 50,000 euros (£45,000) over the incidents in the Valencia game.
Ajax won that match 2-1 but Getafe won the tie 3-2 on aggregate.