MIAMI GARDENS, Florida – McWilliams Arroyo basically took target practice Saturday night on Julio Cesar Martinez’s late replacement.

If nothing else, Arroyo stayed sharp by getting in the ring and ensured that he didn’t waste another training camp for a fight with Martinez, the WBC flyweight champion. Puerto Rico’s Arroyo (21-4, 16 KOs) battered Abraham Rodriguez until Rodriguez’s handlers had seen enough in the fifth round of their scheduled 12-round on the Canelo Alvarez-Avni Yildirim undercard at Hard Rock Stadium.

Referee Sam Burgos stopped their fight at 1:41 of the fifth round.

Arroyo won the WBC interim flyweight title by beating Rodriguez. The 35-year-old Arroyo also remains the mandatory challenger for Martinez, who has pulled out of two fights with Arroyo.

Mexico’s Rodriguez (27-3, 12 KOs) took this difficult fight on extremely short notice and at a higher weight. He fought at flyweight earlier in his career, but he has mostly boxed in the strawweight and junior flyweight divisions in recent years.

Arroyo was supposed to challenge the star of their division in Martinez. Mexico’s Martinez (17-1, 13 KOs, 1 NC) pulled out of their fight Thursday for the second time in seven months – this time with an injury to his right hand.

Martinez and Arroyo were first scheduled to box August 15 in Tulsa, Oklahoma. Martinez withdrew from that main event late in August due to what he described to BoxingScene.com as a gastrointestinal issue.

Arroyo’s thudding right hand buckled Rodriguez’s legs nearly halfway through the fifth round. An aggressive Arroyo followed up by landing an array of power shots, which prompted Rodriguez’s trainer to ask for the fight to be stopped.

Arroyo’s left uppercut backed up Rodriguez barely a minute into the fourth round. He rocked Rodriguez with a right hand while Rodriguez was backed against the ropes later in the fourth.

Rodriguez took a knee with 56 seconds to go in the fourth after taking several hard body and head shots from Arroyo.

Arroyo landed a right hand that made Rodriguez tie him up in the first minute of the third round. Rodriguez continued initiating clinches for much of the third round.

With just over 30 seconds to go in that third round, Arroyo landed a left hook to the body and a right hand up top that affected Rodriguez.

Arroyo pressured Rodriguez for much of the first two rounds and landed the harder cleaner shots. Rodriguez connected with an overhand right that seemed to give him some confidence toward the end of the second round.

An accidental clash of heads caused Rodriguez to turn away from Arroyo with just over a minute remaining in the first round. Burgos gave him time to recover, but the action resumed soon thereafter.

Keith Idec is a senior writer/columnist for BoxingScene.com. He can be reached on Twitter @Idecboxing.