Vichai Srivaddhanaprabha, two members of staff, the pilot and a passenger, all died after the crash outside the east midlands Club's ground on Saturday night.
Mahrez scored the only goal against Tottenham, pointing to the sky afterwards, and gave his thoughts in an emotional interview following the game.
"It's been very, very difficult for me. It's not easy to hear this type of stuff," Mahrez said.
"The boss (Leicester owner) was very special to me. I spent four and a half years there.
"I have many memories of him. He was such a good person; a good human.
"It's very, very, very sad. That's why when I scored, I put my hands up to the sky for him. He did a lot for me and for Leicester.
"It's difficult to speak about it - very sad. He was like a dad for us - very, very special. Believe me, he was such a good person.
"He had a very big heart. I was heartbroken. It was shocking for me to hear this news and for the other people who died with him.
"It's a difficult situation and I am with Leicester and the families of the victims. It's not an easy situation.
"I knew he would have wanted me to play. He was very passionate about football.
"It's difficult but I kept thinking about him. It's been difficult to sleep as well."