Errol Spence Jr unified the IBF and WBC welterweight belts with a split-decision victory over Shawn Porter.

In a blockbuster showdown between two welterweight world champions at Staples Center in Los Angeles, Spence (26-0-0) triumphed as two judges scored the fight 116-111 in his favour.

One judge gave Porter (30-3-1) a 115-112 victory but the previously undefeated WBC holder suffered his first defeat on Saturday.

The fight was rough and rugged from the start as Porter did a good job of closing the distance on Spence early. However, the latter welcomed the contact and fought through some heavy exchanges on the inside in the early going.

There were several rounds that could have gone either way early in the fight, but the ultimate difference was likely an 11th round knockdown of Porter by Spence on a vicious left hook.

Spence now may have to face off with Danny Garcia in his next fight, but the two matchups most boxing fans will want to see will be with either of the other two welterweight champs in Manny Pacquiao or Terence Crawford.

In the super-middleweight division, incumbent WBC champion Anthony Dirrell fell to challenger David Benavidez by TKO in the ninth round.

Dirrell (33-2-1) fought through a significant cut under his right eye early in the fight, but ultimately the doctor stopped the fight.

Benavidez remains a perfect 22-0-0 with the win. He also became the youngest two-time super middleweight champion of all time.