Milwaukee's night seemed to turn on one play.

Having already scored one run to cut the Red Sox lead to 4-3 in the third, the Brewers had the bases loaded against John Lackey with nobody out. Casey McGehee hit a shot to the left of second baseman Dustin Pedroia, a ball that looked like a sure single and at least one more run.

But Pedroia stabbed it with a dive and started a double play.

The tying run scored, but Lackey, given an apparent boost by the play, retired the next 14 hitters before an eighth-inning single and the Red Sox blew the game open, beating Milwaukee 10-4 Friday night.

"Huge play," Milwaukee manager Ron Roenicke said. "We've got a chance to have a big inning there and it's not the first time I've seen him do it. The guy can play."

Roenicke was a coach with the Los Angeles Angels when Lackey was having success there. Before the game, he said Lackey's early-season struggles surprised him "because I saw him so good for so many years. I always think of him as a great pitcher."

After the game, he said, "We saw (Lackey struggle) at the beginning and then the last few innings is the guy I know. He got on a roll and that's the pitcher that I always saw."

His own pitcher, Shaun Marcum, labored through a 44-pitch first inning and was done for the night with a left hip flexor injury. He was replaced by Marco Estrada (1-4), who pitched four innings.

Marcum "said he's OK but it was bugging him," Roenicke said.

Marcum, who brought a 7-2 record into the game and wasn't involved in the decision, indicated he doesn't think the injury is serious.

"I didn't want to come out after the inning," he said, "but we wanted to be smart about it, not do anything stupid and go out there and take a chance of hurting it worse or actually doing something and missing more time."

Asked about missing a start, Marcum said, "I don't think so. I'll come in (Saturday) and see where we're at. Hopefully the tightness will be out of there for the most part. I'm sure there will still be some in there but not near what it is now, hopefully."

Tied at 4 in the fifth inning, the Red Sox went ahead 5-4 on Adrian Gonzalez's leadoff homer, his 15th of the season. They added two runs in the sixth and three in the seventh.

Boston increased its AL East lead to 2½ games over the New York Yankees, who lost 3-1 to the Chicago Cubs. Milwaukee's lead in the NL Central was cut to a half game over the St. Louis Cardinals.

Lackey (5-5) improved to 3-0 since coming off the disabled list. Matt Albers pitched the ninth after Lackey allowed four runs and eight hits in eight innings.

The Red Sox's potent offense resurfaced after they scored just seven runs in a three-game series at Tampa Bay, although they won two of them. During their nine-game winning streak going into that series, they averaged 9.2 runs.

But the victory may have been costly for the Red Sox, who lost two starters. Left fielder Carl Crawford departed with a Grade 1 left hamstring strain, the least serious kind according to manager Terry Francona, suffered while beating out an infield single in the first. Third baseman Kevin Youkilis, who was feeling ill, was replaced by Drew Sutton in the top of the fifth.

Two other Red Sox players left Thursday night's 4-2 win at Tampa Bay — starter Clay Buchholz with back problems and shortstop Jed Lowrie with a shoulder injury.

The Brewers scored two runs in the first on a single by Nyjer Morgan, a double by Prince Fielder and a two-run single by Casey McGehee.

The Red Sox tied it in the bottom of that inning on a leadoff homer by Jacoby Ellsbury, a single by Gonzalez and an RBI double by David Ortiz.

Boston went ahead 4-2 in the second on a walk to Pedroia, a double by Gonzalez and a two-run single by Youkilis.

Milwaukee tied it in the third. Lackey allowed singles to the first four batters — Rickie Weeks, Morgan, Ryan Braun and Fielder — for one run. Then Pedroia made his rally-killing play.

Notes: The first inning lasted 43 minutes. Marcum threw 44 pitches and Lackey 25. ... Braun extended his hitting streak to 10 games with his single in the third. ... The Brewers lost for the 11th time in their last 12 games at Fenway Park.