For the better part of 12 rounds, Darryl Tyson and Freddie Roach stood in the middle of the boxing ring at the D.C. Convention Center and furiously traded blows.

And when it was over, Tyson emerged -- albeit barely -- with a successful defense of his World Boxing Council Continental Americas lightweight championship by scoring a tough unanimous decision.

"I had the better punching, but he hung in there," said Tyson (24-1), a Washington native who likely will earn a shot at International Boxing Federation champion Jimmy Paul. "I was surprised he didn't go down."

Roach, a gutsy veteran from Las Vegas who had won four of his last five fights, fell to 40-11.

In earlier bouts, welterweight Tommy Ayers of Cincinnati (31-1) twice knocked down Leland Hart (16-8-3) of Sacramento, Calif., en route to a 10-round unanimous decision, and lightweight Carlo Cartajena of New York (5-1) scored an eight-round decision over Jocko King of Washington (15-7). In the professional debut for two welterweights, Jose Ortiz of Washington shook off a second-round knockdown to earn a technical knockout one minute later over Ray Bright of New Haven, Conn.

Although Tyson used his superior quickness to repeatedly connect viciously with both hands to Roach's head and body, his opponent never was visibly stunned. Instead, Roach simply bulled his way inside and continued his strategy of working Tyson's body.

Tyson did manage to draw blood from Roach's nose and left brow in the middle rounds, but he felt his own performance was off.

"My timing wasn't right," Tyson said. "I was a little anxious with my right. I needed to take my time more . . . But that was the best fight I've had since September a 12-round knockout over Nick Parker of Atlantic City ."

In the undercard bouts, Ortiz made an exciting professional debut, rallying from a second-round knockdown to knock out Bright, another rookie, at 2:22 of the round.

Ortiz had a substantial reach advantage, but after a timid first round, allowed Bright to get inside and was felled by a sharp left jab one minute into the second round. Following a standing eight count, however, Ortiz plowed into Bright, knocking him into the ropes with three solid head shots before referee Frankie Kelly stopped the fight.

Cartajena earned his decision by landing several powerful blows to the head and body of King in the early rounds.

The slender Cartajena stunned King with three head shots in the first round and appeared on his way to a knockout when he opened up a cut over King's right eye in the fourth.

But King, who showed a surprising lack of mobility or power, nevertheless hung on grimly, and even sent Cartajena against the ropes with a fifth-round flurry. Yet Cartajena's quickness allowed him to ride out that attack and solidify his lead by connecting with two solid rights in the eighth.

Ayers' bout against Hart was a contrast in styles. Ayers was the clear aggressor, stalking his opponent for most of the fight and pinning him to the ropes with combinations in almost every round.

Yet Hart, whose unorthodox, defensive tactics clearly baffled Ayers, was able to ward off any serious blows. He was knocked down briefly by powerful jabs in the second and sixth rounds, yet got back to his feet almost immediately.

Organizers estimated the crowd at 4,500.