The Norwegian sat out a competitive match for the first time since arriving at the Club in the summer as we battled to a 0-0 draw in the Danish capital.
The striker has scored 20 goals in his 13 appearances but with City in a commanding position in Group G ahead of the match, Guardiola chose to leave him on the bench.
Julian Alvarez started up top but his impact was limited by Sergio Gomez's red card that left us down to 10 men for the last hour of play. The Argentine striker worked tirelessly off the ball as the Blues eventually took a point from the Parken Stadium.
Asked about Haaland's absence in his post-match press conference, the manager explained how the No.9's heavy workload has affected him.
"He finished the game against Southampton so so tired and he didn't recover well these two, three days," he said.
"Yesterday was not good, today was a little bit better but not perfect and we decided not to take the risk."
Click on the video above to hear what Guardiola had to say in the Danish capital...