Kentucky Derby winner Giacomo finished third, ending his bid to attempt a Triple Crown try in the Belmont Stakes.
The frightening scene occurred as a full field of 14 3-year-olds turned for home. Scrappy T, ridden by Ramon Dominguez, went wide off the turn as the jockey was whipping left-handed, and the gelding drifted into the path of Afleet Alex, who was just behind.
Afleet Alex's front legs buckled and the colt almost fell, nearly unseating jockey Jeremy Rose as the crowd gasped.
"I thought for sure we were going to have a roll," Rose said.
But somehow, Rose managed to stay on as Afleet Alex regained his momentum, neatly cut to the inside and went on to win the second leg of the Triple Crown.
With tragedy incredibly averted such stumbles have led to the deaths of horses and jockeys being trampled Afleet Alex sailed home with a sweet 4@3/4-length victory, marking the fifth straight year the Preakness favorite has delivered.
Giacomo, who staged the second-biggest upset in Derby history two weeks ago at 50-1 odds, was unable to pull off another win as the gray colt never threatened.
And for just the third time in nine years, the Belmont will be run without a Triple Crown on the line.
Rose thrust his arm in the air after crossing the finish line, and then said he was amazed Afleet Alex was able to recover.
"He's just that athletic and I was just that scared," Rose said. "He's just an amazing horse that I think put all doubters to shame there."
While Giacomo's Derby win was a stunner, Afleet Alex's made perfect sense. The son of Northern Afleet ran a sensational race in the Derby as the second choice behind favorite Bellamy Road, only to be caught in the final strides by Giacomo and Closing Argument at almost 72-1.
But not this time, not even after being banged around.
Afleet Alex, now headed to the Belmont in three weeks, covered the 1 3-16 miles in 1:55.04, well off the record of 1:53.40.