SAN ANTONIO – Rolando Romero made Anthony Yigit pay Saturday night, as promised.

A day after some more weigh-in drama, the heavy-handed Romero remained unbeaten by knocking out the absurdly overweight Swedish southpaw in the seventh round of what went forward as a 140-pound bout on the Jermell Charlo-Brian Castano undercard at AT&T Center. Las Vegas’ Romero (14-0, 12 KOs) dropped Yigit three times – once in the fifth round and twice during the seventh round – before referee Rafael Ramos stopped their scheduled 12-rounder at 1:54 of the seventh round.

Yigit (24-2-1, 8 KOs) lost by technical knockout for the second time in eight years as a pro. Russia’s Ivan Baranchyk (20-2, 13 KOs), then the IBF junior welterweight champion, stopped Yigit after the seventh round of their World Boxing Super Series encounter in October 2018 in New Orleans.

The crowd booed loudly after Romero recorded his knockout, but he wasn’t fazed by that harsh reaction.

“I fought a tough kid above my weight class,” Romero told Showtime’s Jim Gray. “I fought a 140-pounder and I f***ing stopped him. Simple as that.”

Yigit unprofessionally came in 5.2 pounds overweight Friday for what was supposed to be a 135-pound title fight for Romero’s WBA interim lightweight championship. Romero came in exactly at the contracted maximum of 135 pounds.

The 29-year-old Yigit had never weighed in at less than 138½ pounds for a professional fight, but the Stockholm resident agreed to meet Romero 3½ pounds lower than that.

Yigit, who fought Saturday night for the first time in two years, replaced an injured Austin Dulay as Romero’s opponent on less than two weeks’ notice. Nashville’s Dulay (14-2, 10 KOs, 1 NC) withdrew from this bout due to a knee injury.

Romero, 25, produced a second straight knockout against a late replacement. He also stopped Phildelphia’s Avery Sparrow (10-3, 3 KOs, 1 NC) in the seventh round January 23 at Mohegan Sun Arena in Uncasville, Connecticut.

Sparrow replaced Justin Pauldo, who was nearly five pounds overweight as well, on about 30 hours’ notice.

Yigit fought courageously against a stronger puncher, but ultimately was overpowered.

A short, straight right by Romero dumped Yigit to the canvas for the second time in the fight, this time with 1:57 to go in the seventh round. Yigit got up quickly, only to find himself on the canvas again after Romero shoved him down.

The action didn’t last much longer, as Romero blasted him with a right-left combination that sent a damaged Yigit down and prompted Ramos to halt the action.

“In the seventh round, I knew it was over,” Romero said. “I swear I thought it was over after that first knockdown [in the fifth round], but I didn’t have time in that round to jump on him.”

Sensing Yigit was hurt after dropping him toward the end of the fifth round, Romero attacked him at the start of the sixth round. Romero’s right hand moved Yigit backward early in the sixth round.

Yigit drilled Romero with a straight left late in the sixth round, but Romero also connected with a straight right that got Yigit’s attention.

Ramos warned Romero for rough tactics after he pushed Yigit to the canvas about 50 seconds into the fifth round. A straight left by Yigit backed Romero into the ropes later in the fifth round.

Romero’s left hook off a break made Yigit stumble backward with just under 30 seconds to go in the fifth round. Less than 20 seconds later, Ramos deducted a point from Romero for hitting Yigit when he called for a break in the action.

Unfazed, Romero landed a left-right combination that sent Yigit to the canvas just before the fifth round concluded. Yigit got up and survived to the sixth round.

A straight left hand by Yigit made Romero wince and back up about 25 seconds into the fourth round. A right-left-right combination by Romero stopped Yigit from punching with just under 1:20 to go in the fourth round.

Romero landed a right and Yigit connected with a left almost simultaneously with approximately 40 seconds to go in the third round. A cut opened beneath Yigit’s left eye earlier in the third round.

A straight left hand by Yigit knocked Romero off balance about 20 seconds into the second round, but that shot didn’t hurt him. Romero’s right hand caught Yigit and forced him to move away with just under 1:20 to go in the second round.

With just over 30 seconds to go in the second round, an off-balance Romero blasted Yigit with a right hand after Yigit connected with a straight left.

Romero mostly missed with his power shots in the first round against an elusive Yigit, who was careful against a superior puncher.

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