Valdez released a huge left hook to knock Berchlt down to the canvas in the 10th round as the unbeaten 30-year-old became a two-weight world champion in an explosive style.
Berchelt was badly hurt and was knocked down earlier on in the fourth round.
He mustered a comeback and fought valiantly in the middle rounds but ultimately, Valdez knocked him down in the 9th and applied a dramatic match ending punch in the 10th round.
In his post-match interview, Valdez said:
"There's nothing better in life than proving people wrong. I have a list of people who doubted me. My idols doubted me.
"Boxing analysts doubted me. They said Berchelt was going to knock me out. I have a message to everybody: 'Don't let anyone tell you what you can and can't do.
"I want to take this belt home, and I'm happy for that."
After the fight, Berchelt, whose only other professional loss came via TKO in 2014, remained down for several minutes but eventually managed to get up with assistance.
He was later taken to hospital, and Top Rank president Todd DuBoef has told ESPN that Berhcelt underwent a CT scan which came back clear.
Valdez wasn't just dominating in the ring, the Mexican was ahead in the judges scorecards throughout. The scores read 89-80, 88-81 and 87-82.
Looking forward, Valdez no doubt will be enjoying his impressive title win but it seems Shakur Stevenson might be next on his list.
The American, who is currently undefeated in professional boxing was watching the bout closely.
The 23-year-old tweeted that Valdez has made him eat his words before saying: "Congrats Champ, I respect what you did tonight surprised me... It's only one FIGHT to make now!"
Oscar Valdez addressed the rumours of this potential fight in his post-match interview.
The new WBC light-featherweight champion said: "Any champion out there, I heard Shakur Stevenson wants to fight. Let's do it. I just want to keep fighting and give the fans what they want."News Now - Sport News