Shane Mosley, 43, knocks out Ricardo Mayorga, 41, in the sixth round

Shane Mosley had a lot to prove — and it turned out he did.

Mosley wanted to prove he was better than his last fight, that he could beat Ricardo Mayorga in their rematch and that he still has what it takes even at his advanced age for boxing.

Mosley, 43, knocked out Mayorga, 41, in the sixth round of their fight at the Forum on Saturday night in front of an enthusiastic crowd that included Michael Buffer as the ring announcer.

Mosley landed a blow that knocked Mayorga to his knees in the sixth round, ending the fight when the referee counted him out at 2 minutes 59 seconds of the round.

Mosley’s most recent bout was his first loss by stoppage, a technical-knockout loss to Anthony Mundine in November 2013.

“All the fans wanted to see me fight,” Mosley said. “I’m glad I was able to put a fight on for them. I have the speed and the power. Look out, I’m coming.

“I think I was a C-plus, but I can do better.”

The two fighters didn’t mind exchanging punches, starting when Mosley landed three right hands in succession in the second round to Mayorga’s face, which seemed to hurt him.

“I think this was a good fight for me,” Mosley said. “I knew after the first punch that it was going to be a knockout. Mayorga was tough.”

Mosley (48-9-1) is a former lightweight, welterweight and super-welterweight champion, but had a 1-4-1 record since 2009. He did knock out Mayorga in the 12th round when they fought in 2008 at Carson.

Mayorga (31-8-1), on the other hand, is a former two-division champion, but had taken breaks of two years and three years from boxing since he was defeated by Mosley.

“The head shots were so easy,” Mosley said. “I was really catching him with so many head shots.”

Earlier on the card, a fight between lightweights Joel Diaz Jr. and Luis Arceo was a one-sided slugfest.

Diaz won in a technical knockout in the fourth round.

Diaz landed enough blows in the first round that caused Arceo to stagger to his corner at end of the 10-round bout.

Diaz continued his assault in the second round, opening a cut on Arceo’s left eye that caused blood to run down his face.

Eventually, Diaz (20-0, 16 knockouts) knocked down a bloody Arceo in the fourth round, the referee stopping the fight at 1 minute 27 seconds of the round after Arceo stumbled as got up off the mat.

A women’s super-bantamweight title fight between Maureen Shea and IBF champion Yulihan Avila didn’t pick up any steam until the final three rounds of the bout.

The 10-round fight went the distance, and despite Shea having a bloody and somewhat swollen face, the judges ruled the fight a split-decision draw.

Shea and Avila exchanged more than enough punches in the eighth round to finally bring alive the crowd, which booed the judges’ decision.