The Egyptian scored from an improbable angle after rounding goalkeeper Cican Stankovic.
Speaking after the game, Klopp said: "When we had the ball we had sitters and didn't score. Then Mo scored the most difficult situation of the whole night - he scored that goal.
"I have no idea [how]. With his quality, how he didn't score one or two of the others I have no clue.
"So many sensational performances. This kind of attitude, it's great. A tricky one but we did it."