BOSTON — Now that he’s rebuilt his pitch count, Chris Sale has to fix his mechanics before his next start in the AL Division Series.

Sale struck out eight over 4 2/3 innings in his final tuneup before the Baltimore Orioles salvaged a split of Wednesday’s day-night doubleheader with a 10-3 victory over the Boston Red Sox.

“This is what these starts have been for — building blocks,” Sale said. “I feel like I’ve gotten enough work in and gotten my pitch count up enough to where I’ll be ready for it.”

But the lefty needs to correct his delivery and the drop-off in his command and velocity, which mostly was in the low 90 mph range.

“As soon I took him out, he was up in the video room,” Red Sox manager Alex Cora said. “It seems like there’s something mechanically going on. He’s not flying his hips the way he usually does. We don’t have too much time.”

Boston won the opener 19-3, dealing the Orioles a franchise-record 112th loss. The Red Sox were 16-3 against Baltimore this year.

“That was an ugly game,” Baltimore manager Buck Showalter said. “I wish we scored nine more runs and beat them 19-3. It’s a crazy game. It’s a great club over there.”

A major league-best 107-52, Boston opens the Division Series at home Oct. 5 against the New York Yankees or Oakland.

Sale left after giving up Adam Jones’ go-ahead, RBI double that made it 3-2 in the fifth. He threw 92 pitches, allowing three runs and four hits.

Sale was limited to one start in six weeks because of left shoulder inflammation but has gradually built up his pitch count in four outings. He had control trouble early, hitting two batters on sliders in the first inning as he allowed two runs.

Trey Mancini had a tiebreaking two-run single off Matt Barnes (6-4) in a three-run seventh and drove in three runs. Tanner Scott (3-2) worked 2 2/3 innings of one-run relief, and Paul Fry pitched three hitless innings for his second save.

In the opener, J.D. Martinez had three of Boston’s season-high 22 hits, including a three-run homer that brought his major league-leading RBIs total to 127. The Orioles (46-112) broke the franchise loss mark set by the 1939 St. Louis Browns went 43-111.

“Man, he doesn’t leave anyone for no one,” Xander Bogaerts said in mock anger after driving in four runs to reach 100 RBIs for the first time in his career and lead Boston to a 19-3 win.

The Red Sox had five homers and nine doubles and matched their biggest scoring output this season. The 14 extra-base hits were the most in the majors this year and the most for Boston since 1950.

In the makeup of Tuesday’s rainout, David Price (16-7) settled down after an early stumble in his final start before the playoffs. He allowed three runs — all in the second inning — six hits and three walks, striking out six before leaving with a 10-3 lead after five.

“Probably I was one pitch from getting taken out of that game,” said Price, who is expected to start Game 2 of the AL Division Series against the New York Yankees or Oakland. “To reel it back in … was big.”

Rafael Devers had four hits and six RBIs, including two homers, and Mookie Betts had two hits to raise his major league-best batting average to .346. Betts also stole a base, making him the second player in Red Sox history with at least 30 homers and 30 stolen bases in a season.

Ryan Meisinger (2-1) got just one out in his first start since he was a sophomore at Radford University, allowing five runs and four hits.

SURPRISE VISITOR — Red Sox TV color analyst Jerry Remy visited the booth and was on the air briefly because “he wanted to thank the fans” for the cards and letters as he undergoes cancer treatment again.

The 65-year-old Remy has had numerous reoccurrences with the disease. He was first diagnosed with lung cancer in 2008.

He plans to return in a limited role next season.

“I think the best way to describe it is: I’m not retiring,” he said. “But, they’ll be limitations. I’m not going to travel anymore.”

MILESTONES — Bogaerts’ 22 homers also is a personal best. … Martinez’s previous career high for RBIs was 104, last year. … Martinez’s 42d homer tied Dick Stuart (1963) for the most by a player in his first year with the Red Sox. … Devers’ six RBIs was a career high.

EMERGENCY PITCHER — Orioles infielder Jace Peterson pitched the eighth in the first game, throwing mostly in the 90 mph range. He gave up four runs and six hits, but he could have gotten out of it with less damage if he had remembered to cover first on a grounder to the right side. Two other hits barely eluded the fielders, including one that went off second baseman Corban Joseph’s glove.

Peterson struck out Christian Vazquez to end the inning.

TRAINER’S ROOM — Red Sox: INF Eduardo Nunez, who hasn’t played since Sept. 19 due to hamstring soreness, ran in the outfield with a team athletic trainer watching between games. Cora said he’ll DH Friday and play third on Sunday.

UP NEXT — Orioles: RHP David Hess (3-10, 5.14 ERA) is slated to start the opener against Houston tonight. RHP Gerrit Cole (15-5, 2.92) is set to go for the AL West champs.

Red Sox: After an off-day, RHP Rick Porcello (17-7, 4.33) is scheduled to pitch the first of three games Friday against the Yankees.