"I felt good as far as body and mind and arm," said Pavano, who led the Twins with 17 wins in 2010.
Josh Beckett started for the Red Sox, going two innings and giving up one run on two hits.
"I thought [he] threw a couple fastballs in the second inning up-middle," Red Sox manager Terry Francona said. "But other than that he was down and pretty good."
In the second inning, first baseman Chris Parmelee, the Twins No. 1 pick in the 2006 draft, doubled and scored on Jason Repko's triple to right field.
"I felt like I was rushing a little bit," Beckett said. "There's some positives there. I wanted to get some groundballs. That means you're keeping the ball down, and I did that. So, it was good."
The Twins added four runs in the fifth. Red Sox left-hander Hideki Okajima opened the inning with consecutive singles to Parmelee, Repko, and Alexi Casilla before Joe Benson's triple. Tsuyoshi Nishioka's single then drove in Benson, giving the Twins a five-run lead.
Nishioka, who batted second and played second base, is entering his first season in the major leagues after playing seven seasons with the Chiba Lotte Marines in Japan. In the first play of the game, he threw out Boston leadoff batter Darnell McDonald.
"'Nishi' made I think three great plays out there. Not easy plays," Twins manager Ron Gardenhire. "The field was wet. The ball was skipping pretty good, and he made them look pretty doggone easy."
Nishioka went 1 for 3, with an RBI.
"I watched him run down the line, and he can fly," Gardenhire said. "We know he can run, but he can fly. He was flying, and that's kind of what we like. We like to run the balls out ... That's a feel-good for us because we like the hustle and he was flying."
The Red Sox cut the lead in the eighth, on Lars Anderson's solo home run. Daniel Nava, who singled, scored on Oscar Tejeda's single, with Tejeda taking third on left fielder Chase Lambin's throwing error. Josh Reddick's single scored Tejeda.
Boston's Mark Wagner hit a solo homer in the top of the ninth to make it 8-4.
Mike Cameron, who missed all but 48 games in 2010 with a lower abdominal strain, went 1 for 3 with a stolen base, after having no steals last season.
"[Cameron] runs down the line, his stride looks good," Francona said. "That was the most exciting thing of the night for me."