After winning a unanimous decision in October, Dawson was just as convincing in winning the rematch Saturday night on HBO World Championship Boxing from the Hard Rock Hotel and Casino in Las Vegas.
Despite a much more spirited effort from Tarver than in their first fight seven months ago, Dawson showed superior power and landed the more accurate punches to stay unbeaten (28-0, 17 KOs) and retain his light heavyweight titles.
"I know I won the rounds but I felt a little out of my element,'' said Dawson, praising his veteran opponent for an improved effort.
"Antonio Tarver said he would be stronger this time and he definitely came back stronger. He fought a helluva fight and did a good job of pressuring me. That took me off my game plan."
Tarver (27-6, 19 KOs) had come back from losses in his career to win rematches against Eric Harding, Roy Jones Jr. and Glen Johnson. The 40-year-old former light heavyweight champion from Tampa predicted he would do the same against Dawson, 26, from New Haven, Conn.
But Tarver didn't rally until the latter rounds and it wasn't nearly enough to erase the wide lead Dawson built on points.
The judges all favored Dawson, with Alan Davis scoring it 116-112 and Duane Ford and Patricia Morse-Jarmin both 116-111.
Dawson's next opponent is up in the air, but a rematch against Glen Johnson is a possibility. Johnson lost a decision to Dawson in a fight many thought should have gone the other way.
"Whoever it is, bring it on,'' Dawson said. " I believe in my skills and I work hard in the gym. Whoever it is that I fight, I'm ready."