The Bhoys lost the Round of 16 first leg 3-0 at Celtic Park on Tuesday and will now need everything to go their way when they head to Turin on March 6 for the return bout.
"It is going to take a miracle," he told Sky Sports.
"We will compete, we will try and score, we will try and make the tie competitive but it is a very tall order now.
"I am bitterly disappointed, I think the scoreline flatters Juventus, but that is the harsh reality of football at this level.
"We were excellent for 75-80 minutes. The second goal is a sucker-punch but the third goal was really poor from our point of view. Some of our football tonight was excellent and I didn't think that there were three goals between the teams."