Marvin Hagler, who has signed to face Thomas Hearns, a former World Boxing Association welterweight champion, this fall, put on a devastating performance yesterday in Atlantic City, N.J.

With Hearns looking on from the audience, Hagler needed just 67 seconds to demolish Hearns' stablemate, Caveman Lee, and successfully defend his world middleweight title.

The victory was Hagler's fifth knockout in a row and seventh in his last eight fights. It was his quickest knockout since a first-round victory over Sugar Ray Seales in Boston in February 1979.

"I believe today that I shook the world," Hagler said. "We took this fight for the exposure. I didn't expect to end it so quickly--I was just kind of happy to get this thing over as quick as I could and go home and see my newborn baby." Hagler has seen his baby daughter only once since she was born five weeks ago.

Hagler then turned to Hearns and said with a smile, "I didn't want too much to show on the tapes so that Tommy wouldn't have something to look at."

Lee still appeared dazed 30 minutes after the fight.

"I just got caught with a lucky punch," he claimed. "I wanted to be the first to dominate the fight but I guess he got me first."