The former Rangers defender was making his United bow during the 1-1 draw after sealing a short-term move last Wednesday.
Though he was awarded the man of the match award at the end of the Ladbrokes Championship clash, his manager was less than impressed with his defending in the build up to Dunfermline’s opener.
Instead of going to close down Kallum Higginbotham as the winger tore forward on the counter attack, Mohsni backed off and allowed himself to be cornered in a two-on-one situation with full-back Ryan Williamson, who took a pass from Higginbotham and delivered a low cross for Nicky Clark to score.
Laszlo told Arabzone: “With all respect to Mohsni, I want to kill him. Honestly, I want to kill him.
“It’s so easy, you cannot lose a one-against-one situation and give a goal. And then after you are again struggling and you again (let someone) run behind.
“This made me crazy and for this reason I need more attention, especially in defence. You cannot play here like (Diego) Maradona, (Lionel) Messi or Cristiano Ronaldo, you must play nasty and this is what I want from Bilel.
“He must be just Bilel who was at Rangers without red cards and punching somebody. I want a nasty Bilel who talks and works and leads other people.”