LAS VEGAS — Super middleweight prospect Gilberto Ramirez blasted away at the body of Giovanni Lorenzo, dropping the veteran once in the third and twice in the fifth of his fifth-round stoppage win in the main event on ESPN2's Friday Night Fights at the Mandalay Bay Resort & Casino.

A rock-fisted, 22-year-old from Mazatlan, Sinaloa, Ramirez (28-0, 22 knockouts) scored his third knockout over the course of his past four fights, and his second straight following February's 91-second knockout of Don Mouton, who was knocked out for the first time in his career.

The end came at the 2:47 mark of the fifth, as referee Jay Nady acknowledged the request of Lorenzo's corner. Ramirez said he wanted to perform well with Saturday night's Tim Bradley-Manny Pacquiao bout happening on Saturday at the MGM Grand.

"It was very important for me to win, and to do it spectacularly on the eve of Pacqauiao-Bradley," said Ramirez, through Top Rank publicist Lee Samuels. "We studied tapes of our opponent, decided to beat him strickly with a body attack."

During the third round, a body shot doubled over Lorenzo (33-7, 25 KOs), who was subsequently bludgeoned relentlessly with both hands by Ramirez before sinking to one knee and taking a count from referee Jay Nady. Lorenzo was dropped twice more in the fifth from a right to the body followed by a left to the head, and then, from a straight left hand, after which Lorenzo's corner threw in the towel.

Top Rank Vice President Carl Moretti said that he expects to bring back Ramirez on the undercard of a 168-pound clash that is being negotiated for July 19 between WBA middleweight titleholder Gennady Golovkin and Julio Cesar Chavez Jr. at The Forum in Inglewood, Calif., on HBO Pay Per View.

On the undercard, 24-year-old Jesse Hart (13-0, 10 knockouts) scored a pair of fourth-round knockdowns during an eight-round unanimous decision over Samuel Clarkson (10-3, 6 KOs), ending the 24-year-old loser's four-fight winning streak.

The son of a legendary middleweight fighter, Eugene "Cyclone" Hart, Jesse Hart won by shutout scores of 80-70 although he said that he was facing a southpaw for the first time in his professional career.

Russian light heavyweight Egor Mekhontsev, who captured the light heavyweight gold medal at the 2012 Olympics in London, scored two knockdowns during his third round knockout over Dwayne Williams. Mekhontsev rose to 3-0 with as many knockouts, and Williams is 5-3 with two knockouts.