Will Middlebrooks and Daniel Nava came up with clutch hits in a three-run eighth inning, rallying Boston to a 6-5 win over the Miami Marlins to complete a three-game sweep.

Middlebrooks, who went 3-for-4 with four RBI, belted the tying two-run homer in the eighth. Nava's single to center scored Ryan Kalish, who set up the go- ahead run with some heady base-running.

The Red Sox won their fifth in a row and dealt the Marlins their 13th defeat in 15 contests.

Jarrod Saltalamacchia doubled to center leading off the Boston eighth. Edward Mujica then replaced Randy Choate on the mound, but Middlebrooks smashed the tying homer on a 2-2 pitch over the wall in center.

Middlebrooks was playing in his 38th game of the season at the major league level and has been splitting time at third base with Kevin Youkilis.

"It seems like he's doing just fine like this," Red Sox manager Bobby Valentine said. "He's keeping sharp, he's watching, he's learning, and when he's in there it doesn't look like he's missing a beat."

Kalish followed with a single to right, but his speed on the bases factored in the go-ahead run. Mike Aviles grounded a ball in the hole on the right side. First baseman Gaby Sanchez flipped the ball to Mujica (0-3) for the out, but Kalish was running on the play and raced all the way to third base. Nava then lined a single to center.

Alfredo Aceves retired the side in order in the ninth to earn his 18th save, with Scott Atchison (2-0) tossed two scoreless frames to get the win.

Giancarlo Stanton homered for the Marlins, who scored three times in the opening inning off Daisuke Matsuzaka, but Carlos Zambrano couldn't hold the advantage.

Matsuzaka allowed four hits and as many runs over 5 1/3 frames, while Zambrano gave up five hits and three runs while walking four through five innings.

Boston's starting pitcher didn't adjust well right away to the searing heat. With a game-time temperature of 92 degrees, Matsuzaka struggled in the first inning when the Marlins stole three bases. Jose Reyes led off with a base hit and sped to third on a groundout to shortstop.

Stanton walked and stole second, and with two outs, Greg Dobbs singled to right field for a 2-0 lead. Dobbs stole second on a poor throw from Saltalamacchia behind the plate and scored on Omar Infante's base hit. Infante also swiped second, but was left stranded.

"It's not about how you start, it's how you finish. Our finish line was very narrow," Marlins manager Ozzie Guillen said. "We have to step it up a notch."

After his hiccup in the first, Matsuzaka retired 14 in a row.

Boston wasted a bases-loaded chance in the first, but got within one in the fourth. Middlebrooks had and RBI single following a pair of hit batsmen, and Aviles lifted a sacrifice fly later in the frame.

Middlebrooks singled in Adrian Gonzalez in the fifth, but Stanton's homer to left and Infante's RBI double, also off the Green Monster in the sixth, gave Florida a 5-3 lead.

Game Notes

Miami returns home to take on the Blue Jays in a three-game weekend series. The Marlins went 1-8 on their last homestand, but they are riding an eight- game win streak over Toronto...The Red Sox host Atlanta this weekend...Middlebrooks has nine RBI over his last five games.