PARIS, NOV. 21 -- American Virgil Hill retained his World Boxing Association light heavyweight title tonight with a unanimous 12-round decision over France's Rufino Angulo.

Hill, now 20-0 as a pro after winning a silver medal at the 1984 Summer Olympics, dominated the fight from the outset and scored the only knockdown in the first round, when he floored Angulo with 10 seconds left. Angulo missed a right and Hill came back quickly with two lefts that put Angulo on the canvas. Angulo got up immediately but took an eight-count before the round ended.

Hill, 23, making his first title defense, moved easily throughout the rest of the fight, scoring mostly with left jabs, and never was seriously threatened. Angulo seemed content to try to block the blows and launched few punches.

Angulo, 31, the WBA's ninth-ranked challenger, fell to 29-9-2.

Hill, of Grand Forks, N.D., used his superior quickness. After the first-round knockdown, neither Hill nor Angulo landed another solid punch.

Judges Nelson Vasquez of Puerto Rico and Jesus Celis of Venezuela both scored it 120-107 for the champion, while Panamanian Rodolfo Hill's card had a 118-111 verdict.