Lyndon Rush's Olympic debut turned sour at Whistler's dreaded 50-50 corner and British driver John Jackson suffered nasty cuts after being raked by the spikes of his brakeman Dan Money as they tipped over.
Money was jettisoned and slid forlornly along the ice.
Driver Jackson said: "It's disappointing because we've had some fairly decent times in the two-man.
"The track is in an amazing condition and it's beautiful to drive. I just made a mistake."
Brakeman Money said: "We were in the top-10 in training and we felt really good. It's a good track. It's fast and challenging, but it's the Olympic Winter Games, so you expect it to be.
"This can happen - it's bobsleigh, it's not ballet dancing. We'll just have to come back for the four-man."
Rush was third after the first run and speeding into medals contention going into Sunday's decisive heats after being given a tremendous push-off by experienced brakeman Lascelles Brown on his second descent of the day.
However, trouble struck on the toughest section of the course and the whoops and cheers from fans perched around the snaking track turned to gasps of horror and groans of disappointment as Rush's sled turned on its side and flipped.
It rumbled around Thunderbird corner upside-down and out of control, slithering over the finish line before Rush and Brown were helped out of their stricken sled by course marshals.
"What do you say?," the 29-year-old former American football player said as he clutched a bloodied and bruised hand.
"I'm so disappointed, I really feel bad for Lascelles because he pushed so well.
"It's the Olympics right, that's big. Everybody tells me that's big. More than anything I like racing and this is a track where I'm good. I had a chance to do well, that's the most disappointing thing."
Brown, who competed for Jamaica in Salt Lake City before switching to Canada and winning a silver medal in Turin, suffered bruising to his muscle-bound back but the physical discomfort was nothing compared to losing the chance of a medal.
"I'm upset, not because of the physical crash but because we were third after the first run. That showed that in his first Olympics this kid had the potential to take the medal."
The first two runs down the menacing ice chute were punctuated by crashes, particularly the first one when Australia II went through 11 of the 16 corners upside down.
Lange, bidding to repeat his performance in Turin where he won both bobsleigh events, showed why he is considered to be the ultimate driving machine.
Times of 51.59 and 51.72 seconds, both men's two-man track records, put him 0.11 seconds ahead of Germany II driven by Thomas Florschuetz. Russia's Alexander Zubkov was third, half a second back while America I, driven by Steve Holcomb was fourth after almost coming to grief on their opening slide.
Thousands of spectators enjoyed bright sunshine and warm temperatures on Blackcomb Mountain for the start of what is always one of the highlights of a Winter Games and big crowds are expected again on Sunday when the medals will be decided.