Boston had 16 hits, and no team has reached double-digit runs this season more than the Sox's 11 times. Ortiz hit the 396th home run of his career and 18th of the season in the fourth inning, a grand slam off right-hander Chris Hatcher, with Marlins starter Ricky Nolasco already knocked out after 3 1/3 innings. Nolasco was charged with nine runs.
Jarrod Saltalamacchia hit his 13th of the season off Hatcher two batters after Ortiz, while Will Middlebrooks entered late and hit his seventh of the year against local product Steve Cishek. All this was behind left-hander Felix Doubront, who moved to 8-3 with six innings of four-run ball.
"My teammates have scored a lot of runs to help me in those kinds of situations when I give up runs," Doubront said. "That helps me. We're a great team."
Ortiz has homered in three straight games, a streak he last matched in 2009. In his last 10 games, he's hitting .394 (13-for-33) with five homers. And it's not as though the muggy day wasn't affecting him.
"The heat was unbelievable out there today," Ortiz said. "I like the heat to play, but it takes something away from you and makes you tired, but we did good today, on a hot day.''
Ortiz moved past Rico Petrocelli for second on Boston's carrer grand-slams list, with 10. Ted Williams is at the top with 17. Including Big Papi's Minnesota days, he has 11 grand slams lifetime.
Ortiz was intentionally walked leading up to a third-inning double by Cody Ross, a hit Ortiz hustled to score on. Before the free pass he had some subtle communication with Marlins manager Ozzie Guillen and bench coach Joey Cora.
"Ozzie's my boy, and Cora, too," Ortiz said. "When I stepped into the box I was expecting them to intentionally walk me and then Cora, he kind of gives me a sign like we're going to pitch to you and I'm, 'Oh, OK. See how that goes.' And the guy throws me the first two pitches for a ball and then they intentionally walk me and I just give him a look like, 'From the beginning we should have just saved some time.'"
"I fell behind in the count a lot and there's not much you can do when you're behind in the count," said Nolasco, who gave up as many hits (nine) as Doubront. "Now that the last two games we've been swinging the bats we haven't been able to pitch. That's just the way the game is and it's frustrating. It's not going well for us right now."
Daniel Nava didn't go deep but went 4-for-5 at the top of the lineup. Ryan Kalish, batting second, added two hits, as did Kevin Youkilis.
Red Sox manager Bobby Valentine isn't a big believer in game-to-game momentum -- not a lot of managers are -- but the Sox are in position to put together a run they haven't had all season.
"We've got a lot of games left," Nava said. "We've got some momentum going, and we'll take the ones when we get them."