GLENDALE — When Vanes “Nightmare” Martirosyan’s scheduled opponent, Juan Astorga, pulled out of Saturday night’s 10-round clash just days before the bout, the Glendale super welterweight prospect didn’t bat an eye.

Instead, he simply battered Astorga’s short-notice replacement, Harrison Cuello, for all of 2:13 of the first round before winning via technical knockout at Buffalo Bill’s Resort and Casino in Primm, Nev. to improve his perfect record to 24-0 with his 15th knock- out.

“We didn’t care [about the change of opponent],” said Martirosyan, whose confidence is at an all-time high since reuniting with highly-regarded trainer Freddie Roach, who prepared him for Saturday’s contest. “We were ready for anything.”

Cuello (18-10-2, 14 KOs), from Bronx, N.Y., by way of the Dominican Republic, came out wild in the first round, but was quickly subdued by the controlled fury of the 23-year old Martirosyan.

“I just didn’t stop throwing punches,” Martirosyan said.

As a prelude to the stoppage, Martirosyan caught Cuello with a right hand and when Cuello lowered his head, Martirosyan connected with right uppercut that buckled Cuello’s knees.

Martirosyan punished Cuello in the corner before chasing him to the opposite corner and delivering the final blows.

“He was out on his feet,” said Martirosyan, whose fight Saturday was shortened to eight rounds after the change of opponent. “I feel very good. It was a very good win.”

Saturday’s abbreviated outing marked the second time in his last three bouts that Martirosyan has delivered a first-round knockout.

He stopped Charles Howe just 80 seconds into the first round on Nov. 1 at Mandalay Bay Resort and Casino in Las Vegas, in what remains the quickest win of his career.

Martirosyan, in what should be a stiffer test, is now set to fight Andrey Tsurkan (26-4, 17 KOs) on June 27 at Boardwalk Hall in Atlantic City in a 10-round affair.