BOSTON -- Big Papi almost looks as if he never missed all that time.
"When you consider eight months down and I don't know how many at-bats he's had, 15 or so and you consider the number of hits he's compiled, it is impressive," Red Sox manager John Farrell said. "He's got such good plate coverage. Against lefties he goes the other way for a double and hits one through the hole.
"He's pretty amazing to watch and he's run the bases well. There's no issues as far as his intensity as well -- as he's run with. He's really given us a lift in the middle of the order."
It was Boston's ninth win in 12 games and came after a 13-0 loss to Oakland a night earlier.
Ortiz is 8 for 16 since returning to the lineup on Saturday for the first time since last August. He missed 71 of the final 72 games last season and all of spring training's with an Achilles tendon injury.
But he doesn't feel that well yet.
"I'm not really concerned with getting injured," he said. "But there's still some concern because I'm not 100 percent yet."
Ortiz has multiple hits in three of his four games.
"I work, man. I work. I'm old enough to know what I need to do to stay there," he said. "Right now I'm not where I want to be, so I'm not trying to juice some balls. I'm trying to stay with what they give me. You see how they pitch me. I got to be patient."
Jon Lester (4-0) got the win despite walking a season-high six and lasting just 5 2/3 innings. He allowed three runs on six hits, striking out five and walking two more than he had in his previous four starts.
Oakland was hurt by another rough start by Brett Anderson.
Anderson (1-4) was hit hard for the third straight start, giving up six runs on eight hits in four-plus innings. In the last three, he's been tagged for 17 runs in 10 2/3 innings.
"It just seems like he's out of sync at times," manager Bob Melvin said. "Just for whatever reasons at times, he loses his command, he gets behind. It looked like that was a little bit of the issue today."
Anderson just feels like he needs to do anything to change his luck.
"I've just got to go out there and maybe help a grandma cross a street or burn my locker or something like that," he said, "and get some better mojo going, because I'm a better pitcher than that."
Andrew Bailey struck out all three batters in the ninth for his fifth save.
It was Lester's 89th career win, matching Babe Ruth for fifth in club history by left-handers.
The Red Sox broke a 3-all tie and chased Anderson with a three-run fifth. Jacoby Ellsbury opened the inning with an infield hit and scored on Shane Victorino's double. Dustin Pedroia reached on an infield hit and Ortiz followed with an RBI single. Chris Resop relieved and hit Mike Napoli with the first pitch before Daniel Nava had a pinch-hit single. After Will Middlebrooks flied out, Jerry Blevins entered and retired the final two batters, leaving the bases loaded.
Josh Donaldson's RBI single made it 6-4 and Young's second homer cut it to one in the eighth.
The Athletics went ahead with three runs against Lester in the fourth on Young's homer that caromed off a billboard above the Green Monster seats, but Boston tied it with three in the bottom of the inning.
Ortiz, back in the lineup after getting Tuesday off, doubled leading off and scored on Napoli's double. Jonny Gomes walked and, one out later, Drew tripled into the right-field corner.
Anderson had left his previous start with a sprained right ankle. ... Melvin said he kept Josh Reddick out of the starting lineup with a tough lefty going now that it looks like the outfielder's worked out of a slump. Reddick was 2 for 4 in each of the first two games after going just 3 for 37 in the previous 10. Reddick struck out pinch hitting. ... Boston recalled RHP Daniel Bard from Double-A Portland before the game and optioned RHP Steven Wright to Triple-A Pawtucket. ... The Red Sox again honored members of the Watertown, Mass., police department. Members stood on top of both dugouts, got a big ovation from fans and both teams. ... Home plate umpire Jerry Layne left the game after being hit on the left hand by a foul tip in the third. Second base ump Mike Estabrook took over behind the plate. ... Anderson was 5-2 with a 2.70 ERA in eight starts against Boston. ... A fan was taken from the stands on a stretcher in the ninth. ... Victorino left in the seventh when his back stiffened up