(CNN) Andy Ruiz Jr. became the first Mexican-American heavyweight world champion Saturday after a stunning upset victory over British boxer Anthony Joshua.

Ruiz, 29, won via a seventh round technical knockout at Madison Square Garden in New York. Ruiz knocked Joshua down twice in the third round and two more times in the seventh round before referee Mike Griffin put an end to the fight.

Andy Ruiz upsets Anthony Joshua to win the heavyweight championship in the 7th round!



(via @DAZN_USA)pic.twitter.com/3pByvV5Y3T — Bleacher Report (@BleacherReport) June 2, 2019

Joshua, 29, was making his US debut and defending his International Boxing Federation, International Boxing Organization, World Boxing Association and World Boxing Organization World Heavyweight titles against Ruiz before the loss.