The final estimate shown on the video board said Josh Reddick's go-ahead homer went 393 feet.

Try convincing the patrons enjoying a meal in the cafe wedged in the second deck of right field that Reddick's home run only traveled that far.

"I think that's about all I got in my 185-pound frame," Reddick said. "It was a two-strike swing so we'll stick with that's all I've got right there."

Reddick continued adding to his status in Boston with a two-run homer off the cafe windows and the Red Sox rallied for a 6-4 win over the Seattle Mariners on Friday night.

Reddick's 10th-inning, game-winning single against the New York Yankees last Sunday gave the Red Sox the lead in the AL East ahead of their rivals, and his homer on Friday extended the lead to two games. The Yankees lost to Tampa Bay earlier Friday night.

Reddick's sixth homer was the cap to a three-homer night by the Red Sox off Seattle starter Blake Beavan (3-3). David Ortiz and Jed Lowrie also homered for Boston.

"I get a kick out of when we use our whole team," Red Sox manager Terry Francona said. "I think it breeds confidence, not just for the guys who played but the others guys know that they'll be there and we can play good baseball. That's good for a ball club."

The trio of homers made up for a rough start from John Lackey, who was knocked around for 10 hits but still managed to pick up his seventh straight victory. For the third time in his last six starts, Lackey (11-8) allowed double figures in hits and he was done after giving up a leadoff single to Mariners rookie Dustin Ackley leading off the seventh inning.

Six of those hits Lackey allowed came in the first two innings, but Seattle wasn't able to capitalize more than Mike Carp's two-run single in the first and Ackley's RBI single in the second. Limiting the damage gave Boston plenty of time to rally.

Down 2-0 in the second, Ortiz got the Red Sox offense going with a solo homer to center field, his 24th of the season and fourth in the last seven games. Lowrie, a late replacement after Kevin Youkilis was scratched with a stiff back, later hit a solo homer in the fifth off Seattle starter Blake Beavan.

But no hit was more damaging than Reddick's shot in the sixth. Beavan (3-3) was ahead in the count 1-2 when he tried to sneak a fastball past Reddick down and in. Reddick quickly dropped the bat head and rattled some folks having dinner.

"He tried to go a little inside to it and it came back over the plate," Reddick said. "I was just kind of looking away but fortunately for me he made a mistake and I didn't miss it."

Ortiz added an RBI single in the seventh that finally knocked out Beavan and concluded the worst start of his young career. Beavan was tagged for six runs and 11 hits, snapping a string of six straight starts going at least six innings and giving up three earned runs or less. He struck out one and walked one but allowed the trio of costly homers.

"A young pitcher facing a lineup like that you can learn more on days like today than on other days when you are sailing along," Seattle manager Eric Wedge said.

After Lackey left, Carp followed with a single off reliever Franklin Morales, but Morales later got Adam Kennedy looking and Daniel Bard struck out Miguel Olivo to end the threat.

Bard got through the eighth before Jonathan Papelbon worked the ninth for his 27th save in 28 chances.

Lackey's been helped during his win streak by getting plenty of run support. His seven straight wins span eight starts and in those outings, the Red Sox have averaged six runs while Lackey is in the game.

"It's fun. It's a good place to pitch," Lackey said. "These guys have been unbelievable all year. You can't say enough about the way these guys swing the bats."

Seattle lost first baseman Justin Smoak in the second inning after he fractured his nose when Jarrod Saltalamacchia's grounder bounced up and hit him in the face.

Smoak was down on the dirt for a couple of minutes and was bleeding after Saltalamacchia's one-hop shot appeared to hit off the bill of his hat and catch the bridge of his nose. Saltalamacchia ran to first with his hands on his head after seeing Smoak fall to the ground.

Smoak later underwent a CT scan at a local hospital. He had returned to the lineup Friday after missing five games with a sore left thumb.

Notes: Sgt. 1st Class Leroy Petry, who was recently awarded the Medal of Honor by President Barack Obama, was honored before the game by the Mariners. His son Austin threw out the first pitch. ... SS Marco Scutaro was also scratched with a stiff back. ... Injured Boston OF J.D. Drew (shoulder) hit during batting practice Friday and is scheduled to do it again Saturday. ... Boston RHP Josh Beckett starts on Saturday in his fourth attempt at getting win No. 10 this season. Beckett beat Seattle 3-1 on July 23 for his ninth win. ... Seattle RHP Felix Hernandez has given up eight earned runs in 13 1-3 innings pitched this season against the Red Sox.