Shawn Porter beats Julio Diaz

Aspiring welterweight contender Shawn Porter bested former lightweight titlist Julio Diaz in a unanimous decision in Thursday's rematch in Las Vegas.

In a television card at the MGM Grand intended to prime fight fans for Saturday's Floyd Mayweather Jr.-Canelo Alvarez blockbuster, Porter (22-0-1, 14 KOs), 25, headlined a show featuring a handful of nearly ready contenders and top prospects. And although it was no walkover, his performance against Diaz (40-8-1, 29 KOs) was more convincing this time around.

After fighting to a surprising draw with Diaz, now 33, last December, Porter raised doubts about his long-term prospects of developing into a top 147-pounder. But in his second go-round with Diaz, he was clearly the better fighter. He routinely beat Diaz to the punch and got the better of exchanges while mostly avoiding clean blows. The official scorecards, in favor of Porter: 98-92, 97-93 twice.

On the undercard, prospect Badou Jack (15-0, 10 KOs) and Marco Antonio Periban (20-1, 13 KOs) fought to a 12-round majority draw. Periban, who challenged for a super middleweight title (and came up just short) against Sakio Bika in his previous outing, was active and continually pressed the action against Jack. Still, Jack seemed to be the sharper fighter, landing the cleaner shots -- and more of them overall -- to bloody and swell Periban's face. But it wasn't enough to sway the judges, who scored it 96-94 Periban, 95-95, 95-95.

A promising fight between undefeated junior middleweights Julian Williams (13-0-1, 7 KOs) and Hugo Centeno Jr. (19-0, 10 KOs) ended in a no-contest after a fourth-round head-butt opened a cut near the left eye of each fighter. Referee Jay Nady noticed the blood from Centeno's cut right away and called for the doctor to examine him, then ended the fight on his advice.

Also, rising junior middleweight Jermall Charlo (16-0, 12 KOs) finished Rogelio De La Torre (10-4, 6 KOs) for a seventh-round TKO. Charlo worked his long jab throughout the fight and was patient in waiting out a game De La Torre. A glancing jab and a hard left hook from Charlo late in the seventh stunned De La Torre, and Charlo followed with an overhand right and a token left hook that sent him sprawling to the mat.

In the opening television bout, Diego De La Hoya, the 19-year-old cousin of 10-time world title winner Oscar De La Hoya, scored a third-round TKO against Luis Cosme in his pro debut. De La Hoya (1-0, 1 KO) flashed speed and combination punching in the junior featherweight bout, finally flushing out a defensive Cosme (8-4-1, 3 KOs) in the third and swarming him in a hail of unanswered punches.

Three 2012 U.S. Olympians who also fought on the undercard, junior middleweight Errol Spence (8-0, 7 KOs), heavyweight Dominic Breazeale (7-0, 7 KOs) and middleweight Terrell Gausha (6-0, 4 KOs) each won by TKO.