It only took dos Santos 64 seconds to put Velasquez out, ending the former champ's reign.
Although the loss is only Velasquez's first, it proved that he may not be as good as we all thought.
Here are a list of other fighters who aren't that great.
Clay Guida may be one of the most entertaining fighters in MMA today.
The scrappy, cave man looking fighter is known for his relentless pace and almost always puts on an exciting fight.
Guida is good, but he proved last night that he still can't get over the hump to become great.
Although he has defeat fighters like Anthony Pettis and Takanori Gomi, Guida has lost to top contenders like Diego Sanchez, Kenny Florian, and now Ben Henderson.
Another lightweight who just can't seem to get over the hump is Melvin Guillard.
Guillard has all the tools to become one of the greatest fighters in MMA today.
Before facing Joe Lauzon at UFC 136, Guillard was on a five fight winning streak and asking for a title shot.
It only took Lauzon 47 seconds to bring Guillard back down to Earth.
There's no denying Rampage Jackson's greatness.
He's defeated former champions like Chuck Liddell, Wanderlie Silva, and Lyoto Machida.
He's also become one of the most well known figures in and outside of the Octagon.
Although Jackson was once great, he's become too predictable.
Jon Jones proved that Jackson was not ready for another title shot.
Although he's always one punch away from a win and is one of the toughest fighters in MMA history, Jackson has not been able to stop anyone since 2008.
Chris "the Crippler" Leben is always just a couple of fights away from a title shot.
Since his time on the first season of The Ultimate Fighter, Leben has been one of the most entertaining middleweights in the UFC.
Leben is know for his rock solid chin and ko ability.
Leben is also known for losing fights that could send him to the next level.
Cain Velasquez has been one of the most dominant fighters in the UFC heavyweight division.
Although his loss last night was his first, it does bring up just how good he was.
Last night wasn't the first time he's gotten rocked or hurt in a fight as Cheick Kongo nearly knocked him out in their fight.
It also brings the question of just how prepared was he for the fight.
Velasquez is still a great fighter and now a former champion. But last night proved that he was not as good as many thought he was.
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