Boston.– Undefeated professional Edwin Rodriguez of Worcester, Mass., boosted his record to 6-0 with a fourth-round technical knockout win over last-minute replacement Anthony Cannon in a bout scheduled for six rounds Saturday night in Dorchester, Mass.

The 23-year-old Rodriguez, who was making his six-round debut, now has a professional record of 6-0 with five knockouts.

The original opponent in the bout, Luis Hodge, was replaced at the weigh-in Friday when he failed his pre-bout physical.

Rodriguez, 162 1/2, dominated from the opening bell, winning the first three rounds handily. He ended it at 2:07 of the fourth with three left-right combinations to the head of Cannon, 166.

“I was looking forward to going six rounds,” said the 6-foot Rodriguez, a former two-time national amateur champion. “But I can’t complain about the fight ending early, because that means I was doing some things well. And that’s the whole point now: learning, improving and then performing in the fight.”

“Edwin looked good,” said Peter Manfredo Sr., Rodriguez’s trainer. “It was the first time he’s had to face a last-minute replacement, and he came through with flying colors.”

Rodriguez, who has lived in Worcester since arriving in the United States from his native Dominican Republic during 1998, considered competing for a spot on the 2008 U.S. Olympic team, but the premature birth of twins, Edwin Jr. and Serena Lynn, changed his priorities.