The 33-year-old Australian's car went airborne after clipping the back of Heikki Kovalainen's Lotus on the ninth lap, somersaulting through the air before crashing into the street circuit's tire barrier at high speed.
Webber appeared to be unhurt and walked from the car, whose front section came away from the chassis. Kovalainen was unhurt and also retired from the 57-lap race won by Red Bull's Sebastian Vettel.
"In the end the thing that surprised me was how early he (Kovalainen) braked, that's the thing which caught me out," Webber told the BBC. "It didn't matter where I was or how close to the tow, I still had everything under control."
The safety car was called out before the race resumed.
Webber, who fell from third to fourth in the standings, was struggling to move up the field after dropping from second to ninth by the end of the opening lap.
Webber did not say who was to blame.
"Well, it always takes two to tango, doesn't it? There's two of us in this incident," he said. "It was a nasty incident."