Toyota Arena in Ontario, California - In a shocker, Rene Tellez Giron scored two big knockdowns and put away undefeated 2016 U.S. Olympian Karlos Balderas in the sixth round. (photos by Stephanie Trapp, Fox Sports).

Balderas drops to 9-1 with 8 KOs, and Giron raised his record to 14-1, 8 KOs

Balderas and Giron was battling hard for two rounds, and then Giron dropped Balderas very hard at the end of the third. Balderas barely got up and was wobbling bad enough where the referee could have stopped the fight. The bell rang once the action restarted.

During the fourth, Giron was hit with a very hard low blow that almost cost Balderas a point.

In the sixth, Balderas was dropped again for a second time and this time he was unable to beat the count.