NEW YORK -- Andy Ruiz Jr., a replacement opponent from the gritty border farming city of Imperial, Calif., pulled off the biggest heavyweight upset of his generation Saturday night, ruining the U.S. debut of England's three-belt heavyweight champion Anthony Joshua by seventh-round technical knockout.
Ruiz (33-1, 22 knockouts) became the first heavyweight champion of Mexican descent by knocking down Joshua four times -- twice each in the third and seventh rounds -- to strip away the World Boxing Association, World Boxing Organization and International Boxing Federation belts from Joshua (22-1).
The victory at Madison Square Garden was nearly as stunning as James "Buster" Douglas' 1990 knockout of Mike Tyson in Japan.
"This is what I have been dreaming about. This is what I have been working hard for. I can't believe I just made my dreams come true," Ruiz, 29, said in the ring as Mexican music blared.
The son of an immigrant contractor, Ruiz said victory came "because of the Mexican warrior I am. I have that Mexican blood in me."
The end came 1 minute 27 seconds into the seventh after Joshua was first dropped and showed exhaustion as a result of Ruiz's pressure, delivered by a 12-punch flurry that included two vicious shots to the head.
Joshua got up, but sustained a follow-up attack that dropped him again. Joshua arose, but retreated wobbly legged to his corner, where he was asked to respond to a command by referee Mike Griffin.
As the dazed Joshua failed to respond appropriately, Griffin waved the fight off. "He didn't want to continue," Ruiz trainer Manny Robles said of Joshua.
Ruiz raised his arms in victory, his rotund, 268-pound body bouncing in a joyous, stunning celebration over perhaps boxing's most physical specimen.
"It means a great deal for me, and for Andy, but it's about more than us," said Robles, who prepared Ruiz through a rushed camp in Norwalk only six weeks long after Ruiz won a co-main event in Carson on April 20.