By Julien Pretot
The world number four never found his stride as clouds started to gather above center court at the Monte Carlo Country Club and he got a few boos from the crowd after going down in just over an hour.
The Scot's terrible first serve percentage was a godsend for Kohlschreiber, who punished his resigned opponent with forehand winners throughout.
Murray should at least get an honorable mention for his honesty after the match.
"I wasn't very good today," he said. "It was the first time in a few years that the court felt so small.
"I just could not find the court. When it's like that, it's difficult to play."
World number 33 Kohlschreiber first broke with a delightful drop shot in the fourth game. From then on, Murray did not appear to put up much of a fight in front of former great Ilie Nastase who was watching from the stands, a pink sweater draped around his neck.
Kohlschreiber wrapped up the opening set when one of his shots hit the tape of the net and bounced above a raging Murray.
"I tried different things. I tried serve and volleying a couple of times. I tried hitting some high balls. It did not really make a whole lot of difference," Murray commented.
The Briton took the first game of the second set as Kohlschreiber fired a forehand long.
But it was then over for Murray, who bowed out with a weak backhand into the net.
Kohlschreiber will next face compatriot Philipp Petzschner for a place in the quarter-finals.
(Editing by Alison Wildey)