Sunday's 13-3 win gave Oakland a three-game sweep over slumping Cleveland, a series in which the Athletics outscored the Indians 30-6.
Yoenis Cespedes drove in a career-high five runs and Brandon Moss had three RBIs to pace Oakland's offense that began with an eight-run second inning Friday night and never let up.
"I would just use the word confident," Moss said of his team's offense. "Everybody's going up there and taking good swings. We have guys who put together some good at-bats who have some pop. That usually leads to runs."
The Athletics, who have won nine of 10, saved their best for the final game, pounding out 12 hits, including seven doubles, and drawing nine walks.
Cespedes' two-run double was the key hit in Oakland's four-run fifth. He also drove in two runs with another double in the eighth.
Moss was 3 for 3 with two walks and scored four runs. He had an RBI double in the fifth, a two-run double in the sixth and a triple in the second.
John Jaso's RBI double in the fourth put Oakland ahead for good while Josh Donaldson, who drove in seven runs in the series, had an RBI single in the fifth and scored four runs.
"All the guys we rely on to knock in runs are doing exactly what they're supposed to do," Oakland manager Bob Melvin said. "That's when we're at our best."
Jesse Chavez (4-1) gave up solo homers to Michael Bourn in the first and Michael Brantley in the fifth, accounting for both runs the right-hander allowed in five innings.
Cleveland has dropped four straight and six of eight. The Indians scored first in all three games, but were no match for Oakland, which leads the AL West with a 28-16 record.
Indians manager Terry Francona is impressed with the Athletics.
"They got it working right now," he said. "They have good starting pitching, they've got a very good bullpen and they are swinging it from one through nine."
Justin Masterson (2-3) allowed seven runs, seven hits and five walks in 4 1-3 innings.
Francona moved Nick Swisher and Carlos Santana, who have battled season-long slumps, down in the batting order, but the changes didn't help the struggling offense, which has scored three runs or fewer 24 times in 44 games.
Santana, moved from cleanup to seventh, was hitless in four at-bats while Swisher, switched from second to sixth, was 0 for 5 and committed an error in the seventh.
Swisher fielded a routine grounder to end the inning and was given a sarcastic cheer by the small crowd of 14,872.
Third baseman Lonnie Chisenhall also had an error, giving the Indians a major-league high 45.
Bourn led off the game with a home run to center that landed in Cleveland's bullpen, but the lead didn't last long.
Moss started the second with a triple. Chisenhall fielded Cespedes' ground ball and his throw landed in the camera bay behind first base. Cespedes was given an RBI.
Masterson walked Donaldson and Moss to start the fourth. Jaso's one-out double put Oakland ahead and Josh Reddick followed with a single for a 3-1 lead.
Oakland put the game away in the fifth, stringing together four hits and a walk off Masterson. Following Donaldson's RBI single, Moss drove in a run with a double and Cespedes' double scored two more.
Jaso and Reddick also drove in two runs apiece.
"Obviously, we got a lot of guys on base this series," Donaldson said. "From top to bottom, we had guys having really good at-bats."
Oakland shortstop Jed Lowrie left the game in the second inning because of a strained neck and was replaced by Nick Punto.
NOTES: The Athletics announced following the game they claimed LHP Jeff Francis off waivers from Cincinnati and he will join the team for its series at the Rays that begins Tuesday. ... LHP Joe Savery, who was expected to go on the paternity list, was optioned to Triple-A Sacramento instead. He pitched two scoreless innings Sunday. SS Jake Elmore (strained left quad) has been moved to the 60-day disabled list. ... 2B Eric Sogard was removed in the eighth inning after fouling a ball off his knee. ... Melvin said LHP Scott Kazmir, ejected in the second inning Saturday, will likely stay on his regular turn and start Friday in Toronto.