Keith Thurman had a test in front of him tonight against crafty southpaw veteran Carlos Quintana, and late in the first round, he pretty much aced it. Thurman floored Quintana on a left hook to the body, and though Quintana survived the round and went a bit longer, it was enough to change Quintana's mind about his chances tonight, resulting in Thurman stopping Quintana at 2:19 of the fourth round.

Thurman (19-0, 18 KO) battered Quintana (29-4, 23 KO) around the ring in the fourth, forcing referee Jack Reiss to eventually stop the fight. Thurman gave himself a "B+ or A-" for tonight's performance, his second win on HBO this year, and said he's ready for anyone in the 147 or 154 pound divisions.

"I'm calling out the world of boxing. Anybody in the world of boxing can get some of Keith 'One-Time' Thurman. You know Al Haymon. Call the number," said Thurman.

It's a good win for Thurman, a 24-year-old prospect who is still raw to my eye, but a guy who has a lot to work with. His raw power is impressive, and he's more patient than he might appear at a glance. Yes, he looks specifically for knockouts, but he doesn't overdo it hunting for one. He's shown an ability to finish, and pounce when the time is right.

Our live coverage of HBO World Championship Boxing continues here, with the Andre Berto vs Robert Guerrero main event up next.