Shawn Porter shocked Devon Alexander by a unanimous points decision in Brooklyn to claim his first world title.

The American, 26, took Alexander's IBF welterweight belt in what was at times an unattractive fight, as he denied the St Louis fighter the space to dictate terms.

Alexander was bloodied by a Porter shot in the fourth round and he returned the favour in the ninth, opening a cut which needed a stoppage for the doctor to check it out.

In the end though Porter stood firm and won with scores on the judges' cards of 115-113, 116-112 and 116-112.