Boston’s Franchy Cordero, right, is greeted by teammates Xander Bogaerts, left, and Rafael Devers, after hitting a three-run home run in the sixth inning against the Athletics on Sunday in Oakland, California. Ross D. Cameron/Associated Press

OAKLAND, Calif. — Franchy Cordero hit a three-run homer off Frankie Montas in the sixth inning and the Boston Red Sox completed a three-game sweep of the Oakland Athletics with a 5-2 victory Sunday.

Rich Hill pitched three-hit ball over six innings and had five strikeouts. Rafael Devers homered and drove in two runs as the Red Sox extended their winning streak to four and got back to .500 (27-27) for the first time since April 22.

“We’ve been playing good baseball the last three weeks, just grinding and using everybody,” Red Sox Manager Alex Cora said. “We’ve still got holes, but on a daily basis, we feel very good about ourselves.”

The A’s lost their seventh straight and fell to 7-23 at home – the worst record in the majors and the second-worst in franchise history through 30 games. The 1920 Philadelphia A’s started 6-23-1 at home.

Montas (2-6) retired 14 of 15 following a rocky first inning before a throwing error by third baseman Kevin Smith in the sixth helped set up Boston’s big inning.

After Devers walked and Xander Bogaerts reached on the error, Alex Verdugo flew out and Trevor Story popped out. A’s Manager Mark Kotsay made a mound visit, then Cordero hit the next pitch – an 85 mph splitter up in the zone – into the left-field stands.

“He got me out the first two at-bats with that splitter, so it was obvious that he was going to try to throw that pitch at some point in that at-bat,” Cordero said through an interpreter. “I was ready for it.”

In his first at-bat, Cordero lined out to first baseman Seth Brown on a ball that had an exit velocity of 100 mph. His home run left at 107 mph.

“That ball was demolished,” Cora said. “There’s a reason he’s getting at-bats, because he’s contributing on a daily basis. It seems like every time he hits the ball, it’s hard.”

Hill (2-3) bounced back from his worst start of the season to beat the A’s for the second time in nine career appearances. The 42-year-old lefty didn’t walk a batter and set down 16 straight after Ramón Laureano’s RBI double in the first before he left following Jed Lowrie’s leadoff single in the seventh.

“Throwing a lot of cutters today, which was good,” Hill said. “It opens up the outside part of the plate, leaves more room for swings and misses with the curveball. It wasn’t like trying to find the strike zone like last game.”

Devers hit an RBI single in the first and homered leading off the eighth.

Montas had seven strikeouts in six innings, but lost his fifth straight. Winless since April 18, he allowed six hits and four runs (one earned).

SHORT HOPS

Six of Devers’ 12 home runs have been solo shots. … The A’s have been shut out three times and held to one run three times over Montas’ last nine starts. … The Red Sox have won eight of their last 11 on the road. … The 1-9 homestand is the second worst in Oakland history. The A’s went 0-6 at the Coliseum from April 29-May 4 earlier this year. … Laureano has a 10-game hitting streak.

TRAINER’S ROOM

Red Sox: Left-hander Chris Sale will throw another bullpen Tuesday, then face hitters Friday. … Right-hander Hansel Robles (back spasms) will pitch an inning for Triple-A Worcester on Tuesday and could rejoin the big league club Thursday. … Left-hander James Paxton (elbow surgery) is throwing up to 120 feet and has been pushing management to allow him back on the mound soon. … J.D. Martinez was given the day off as part of Cora’s plan to rest his veteran players over the next week.

Athletics: Outfielder Stephen Piscotty (calf strain) has progressed to hitting in the cage, but will remain in Oakland to continue his rehab during the team’s road trip.