The midfielder left Fiorentina for Fener on deadline day Friday.
Illicali said, "We have added a valuable player to our team. Amrabat has been our dream for a long time and we wanted to see him at Fenerbahçe. It is an important transfer, but it has been a long process. We spoke with Sofyan months ago and had a meeting with him.
"The two parties immediately understood each other regarding their intentions and future objectives. Although he received very serious offers after that meeting, he did not compromise and kept his word: he always expressed that he wanted to arrive here as soon as possible.
"We promised him to Mourinho and here he is, he was the Portuguese's number one request. Sofyan rejected all 10 offers and stood up, saying: 'I want to go to Fenerbahce'. In the end Fiorentina wanted to keep him but he wanted to keep his promise. Despite this, in order not to leave Fiorentina in difficulty, he played an incredibly difficult game in the Conference League with the Viola who were left with 9 men.
"Frankly, I was very impressed."