Vernon Forrest also successfully defended his WBC super welterweight title, stopping Italy's Michele Piccirillo at 2:21 of the 11th round after landing two crushing right hands.
Tarver used a series of combinations to score a technical knockout victory over Danny Santiago of Ocala, Fla., at 2:53 of Round 4 at Foxwoods Arena.
Tarver (26-4) moved methodically in the first two rounds, rarely throwing more than one punch at a time and barely fazing Santiago (29-4-1).
In Round 4, Tarver used a combination to put Santiago down. Santiago got up, but Tarver finished him off with another flurry of combinations that dropped Santiago to one knee. Referee Steve Smoger immediately called a halt to the bout.
It was the first title defense for Forrest (40-2). The former Augustan won the WBC crown with a unanimous decision over Carlos Baldomir in July. Forrest landed a looping right hand midway through the fourth round that stunned Piccirillo (48-4), but the challenger quickly regrouped.
Forrest landed a similar punch near the end of the fifth round, but with less authority.
In the sixth round, Forrest delivered a blow that was close to being in the back of the head that dropped Piccirillo to one knee, but referee Arthur Mercante Jr. ruled it was a clean punch that led to the knockdown.
Piccirillo was wobbled by a right hand in the seventh, but stayed on his feet. In the ninth, Forest dropped Piccirillo with a stinging right hand for the second knockdown of the bout. Forrest continued to dominate the bout until putting Piccirillo away in the 11th.