On his second qualifying lap of Q1 Perez lost the rear of the car turning into Sainte Devote, slapping the left-rear corner of his Red Bull RB19 into the barriers.
Perez's accident brought out the red flag and caused sizeable damage to his car.
"Unbelievable day. I cannot believe what I've done," Perez responded to the costly incident.
"It just caught me by surprise, just getting that rear out of shape, especially really late into the corner.
"It's a way of how we were trying to get the lap time out of it, but I just went over the limit and I became a passenger. There was nothing else I could do because it was really late in the corner, and I could not cut the corner or go out of the corner."
To make matters worse for Perez, the closeness of the grid and the rapid track progression dropped the Mexican's first flying lap down to last, meaning he will face an impossible task to salvage a result on the narrow streets of the principality.
"Yeah, it came around as a big surprise," Perez replied when asked if he was surprised that his banker lap left him last on the charts.
"Saying that isn't an excuse. I should have done better today, and all I can say I'm very sorry to my team, because you put so much energy, so much work preparing everything, and then you just disappoint everyone like this.
"I'm super disappointed today with myself and I know that tomorrow it's going to be an impossible race."
Team principal Christian Horner believes Perez paid the price for trying to carry too much speed through Turn 1.
Source: Autosport