McGirt and Nunn Win Titles : Boxing: Brown loses welterweight crown. Agoura Hills fighter wins as super-middleweight.

James (Buddy) McGirt won the World Boxing Council welterweight title with a unanimous 12-round decision over defending champion Simon Brown on Friday night.

Also on the card, Michael Nunn, the former middleweight champion, stepped up to 168 pounds and knocked out Randall Yonker to win the North American Boxing Federation super-middleweight title.

McGirt sent Brown to the canvas in the 10th round with two thudding left hooks, the first leaving Brown standing but helpless, and the second crashing against his jaw and dropping him to the mat.

Brown got up and lasted the final seconds of the round.

Brown won the International Boxing Federation welterweight title in 1988, lost it in March to fight Maurice Blocker and knocked Blocker out to win the WBC welterweight title. He hadn’t been defeated since 1985, when he lost a decision to Marlon Starling.

But against the stronger, quicker and harder-punching McGirt, he never had a chance. Afterward, Brown was taken to Valley Hospital for observation.

“That,” said former heavyweight champion Mike Tyson at ringside, “was one of the best exhibitions of boxing talent we’ve seen in a long, long time.”

McGirt had said before the bout that he couldn’t imagine returning to his home in New York without the championship.

Brown was 34-1 with 26 knockouts, but never had a chance against McGirt, who would stop his flashing movement only long enough to hammer Brown with crushing blows, and then dance away.

“They said I couldn’t do it,” McGirt said. “They said I wasn’t strong enough.”

He was much too strong for Brown, however, who announced after the fight that it was his last as a welterweight and he would fight at 154 or even 160 pounds.

McGirt, whose lost a fight early in his career and then was stopped by Meldrick Taylor in 1988, is 55-2-1 with 43 knockouts.

Nunn, who two years ago seemed headed for boxing stardom but was knocked out by James Toney in his most recent bout May 10, was a bit slower in his heavier debut, but still much too fast for Yonker, a little-known brawler from Mobile, Ala.

Nunn won nearly every round with a right jab and landed 25 consecutive punches to Yonker’s head in the 10th round, finally knocking him down.

Yonker stayed down until the count of 10, got up, sat on a stool against the ropes and reached through the ropes, a huge smile on his face, to shake hands with Tyson.

The old Nunn dazzled with his hand speed. Friday night’s version used the same combinations he had thrown to win and then defend the IBF middleweight title five times.

But those punches, once almost too fast to see, were decidedly slower against Yonker, who ducked or picked off many of them.

Officially, it was a knockout. But unofficially, Yonker was too tired to stand up anymore.

And there was more controversy following Nunn, who has had plenty since leaving the Van Nuys-based Ten Goose Boxing Club in 1990. He goes on trial Dec. 13 for an alleged attack on his former fiancee at his Agoura Hills home.

Friday night, the rumor spread that Nunn had stayed out all night Thursday, coming back to his hotel at dawn. Chuck Minker, an official with the Nevada Athletic Commission, said he had heard the rumor and was told by oddsmaker Jimmy Vaccaro that was the reason Nunn dropped from a 15-1 favorite Thursday to only a 9-2 favorite.

Nunn improved to 37-1 with 25 knockouts. Yonker is 23-2.