LAS VEGAS – Delante “Tiger” Johnson showed some power in his debut as a full-fledged welterweight Saturday.

The undefeated Cleveland native dropped Kendo Castaneda twice during the fifth round, when their scheduled eight-rounder ended on the Mikaela Mayer-Sandy Ryan undercard at Fontainebleau’s BleuLive Theater. Six of Johnson’s previous seven fights went the distance, but he was more assertive and looked for a knockout while competing at a higher weight.

Johnson improved to 15-0 and recorded his seventh knockout once referee Raul Caiz Jr. halted the action exactly two minutes into the fifth round. San Antonio’s Castaneda (21-9, 9 KOs, 1 NC) lost inside the distance for the third time in 12 years as a pro.

An aggressive Johnson unloaded power shots in combination early in the middle minute of the fifth round.

He then drilled Castaneda with a right to his body that made Castaneda take a knee with 1:25 to go in the fifth round. Castaneda beat Caiz’s count, but Johnson landed another right hand that sent Castaneda to the canvas again with 1:03 to go in the fifth round and ended their fight.

Johnson, 26, controlled the action in a one-sided fourth round. He hurt Castaneda with his right hand to Castaneda’s body with about 25 seconds to go in the fourth round, which made Castaneda move away from him until it ended.

Castaneda came forward again in the third round, but he didn’t land many clean punches on the taller, rangier Johnson. Johnson’s jab was consistently effective during a second round he won with ease.

Castaneda pressured Johnson throughout the first round. Johnson jabbed and mostly moved out of the way of Castaneda’s right hand in the opening three minutes.

In the bout before Johnson’s win, junior lightweight prospect Dedrick Crocklem stopped Dionne Ruvalcaba in the first round of a scheduled four-rounder.

Croklem (2-0, 2 KOs), a 20-year-old southpaw from Tacoma, Washington, teed off on Ruvalcaba for two-plus minutes. He bloodied Ruvalcaba’s nose and prevented Ruvalcaba from landing any damaging punches.

Referee Robert Hoyle exercised caution and stepped between them to stop their bout 2:50 into it. Ruvalcaba protested the stoppage because he was still standing and hadn’t taken a hard punch in the immediate moments before Hoyle stopped their fight.

Ruvalcaba, of Brownsville, Texas, slipped to 2-2 (1 KO).