David Ortiz hit a grand slam and Mike Aviles added a three-run shot as Boston steamrolled Miami, 15-5, in the middle test of a three-game interleague series.
Will Middlebrooks contributed a two-run blast and Cody Ross clocked in with a three-run double for the Red Sox, who have won the first two in the set and six of seven overall thanks to a season-high in runs scored.
Felix Doubront (8-3) was the beneficiary of the outburst, winning despite allowing nine hits and four runs over six innings.
"My teammates scored a lot of runs to help me and in this kind of situation where I give up runs too, that helps me," said Doubront. "We're a great team."
The victory pulled Boston out of the AL East basement, moving ahead of Toronto, which lost at Milwaukee.
Gaby Sanchez knocked in a pair, while John Buck and Logan Morrison both went deep for the Marlins, who dropped their 12th game in the last 14.
"We just need to find a way to win," Morrison said. "We've got to find a way to come out of it and just get one."
Ricky Nolasco (6-6) was tagged in defeat for nine hits and nine runs over just 3 1/3 frames.
The Red Sox broke open a close game with a six-run fourth. Aviles singled to start, moved to third on a Daniel Nava hit, then scored on a Ryan Kalish single. Adrian Gonzalez followed with a hit to load the bases and Ortiz launched his round-tripper to right for an 11-4 contest. After a Ross fly out, Saltalamacchia cleared the wall in deep center for an eight-run margin.
Nick Punto scored on a wild pitch in the fifth for a nine-run game.
Buck greeted Clayton Mortensen with a seventh-inning solo homer, but Middlebrooks countered with a two-run shot in the home eighth and the hosts led 15-5.
Mark Melancon ended the madness by turning in a 1-2-3 ninth.
Giancarlo Stanton's first-inning double-play grounder gave Miami its initial run in the first inning, and it was 2-0 for the visitors in the second as Justin Ruggiano hit a leadoff double and later scored on a Sanchez groundout.
The Sox moved ahead for good in the home half when Aviles cleared the Green Monster for a three-run homer. Saltalamacchia and Kevin Youkilis reached with back-to-back two-out base hits before the blast.
Boston went up 6-2 in the third. Nava and Kalish singled and Ortiz was given a free pass ahead of a bases-clearing double from Ross.
Morrison began the top of the fourth with a homer, then Sanchez singled in Ruggiano for a 6-4 game.
Since interleague play began in 1997, the Sox boast the fourth-best record at 158-121 and lead the Majors with a 113-63 mark since 2003...The slam by Ortiz was his 11th career homer with the sacks full, and was his 396th career home run, tying him with Joe Carter for 52nd on the all-time list...Red Sox second baseman Dustin Pedroia was scratched due to discomfort in his right thumb...Nolasco went 4-2 with a 4.04 earned run average in his first eight interleague starts, but over 10 starts since then, he is just 2-8...Game-time temperature was a scorching 96 degrees.