BALTIMORE -- Chris Sale received a standing ovation from a large contingent of Boston Red Sox fans at Camden Yards.

They appreciated another dominant performance by the left-handed ace.

Sale became the first American League pitcher with 300 strikeouts in a season since Pedro Martinez in 1999, and the Red Sox completed a three-game sweep of the Baltimore Orioles with a 9-0 victory on Wednesday.

When the Los Angeles Angels lost to the Cleveland Indians later Wednesday, the Red Sox clinched a playoff berth.

Sale (17-7) struck out 13 and tied a career high with his 17th victory. He allowed only four hits and did not walk a batter over eight innings. Sale joins Martinez as only the second pitcher in Red Sox history with 300 strikeouts.

"I appreciate it. I don't want to downplay it or anything," Sale said. "We have still have a lot of work to do. We have quite a few games left and hopefully beyond that. Keep your eye on the prize and look back on this when it's all said and done."

Mookie Betts and Deven Marrero homered for Boston, which has won 11 of 14 and edged closer to clinching a spot in the postseason. Dustin Pedroia snapped an 0-for-18 skid with a two-run double in the eighth.

Red Sox designated hitter Hanley Ramirez, who had been bothered by left arm soreness, was back in the starting lineup for the first time in six games. He went 3-for-5 with three RBIs.

First-place Boston (88-64) remains three games ahead of the second-place New York Yankees in the AL East.

"Given where we are in the standings and what is at stake, every win is important," Boston manager John Farrell said. "Just getting into the playoffs is not our goal. Certainly it is a stepping stone to other things that we have our sights set on. We still have a lot of work ahead of us."

Orioles rookie Trey Mancini went 2-for-4 and extended his career-high hitting streak to 10 games. Adam Jones added two hits.

It was another disappointing series for Baltimore, which has lost 12 of 14 and is free-falling out of the wild-card race. The Orioles were also shut out for the second consecutive night.

"(Sale) is one of the best pitchers in the game, and couple in the fact that we're not really operating on all cylinders offensively, that's for sure, you end up with a shutout," Orioles manager Buck Showalter said.

The Red Sox were only 4-for-14 with runners in scoring position, but they didn't need much offense with Sale on the mound.

Baltimore starter Wade Miley (8-14) didn't allow a hit until Andrew Benintendi flared a single to lead off the fourth. Betts followed with his 23rd homer of the season over the left field fence. Marrero hit another two-run shot that inning and the Red Sox led 4-0.

A pair of walks with one out in the fifth ended Miley's night. Mike Wright entered and gave up a two-run double to Ramirez that extended the lead to 6-0.

Miley allowed six runs and four hits with four strikeouts and four walks. It was the 19th time in 31 starts he has thrown five innings or fewer.

"I walked four guys and gave up two home runs," Miley said. "That's it."

This night, however, belonged to Sale, who pitched eight innings for the seventh time this season. At the end of the day, he was more happy about sweeping a division rival than the number of strikeouts he accumulated this season.

"It's huge, especially going into an off day," he said. "Win the first series on the road, sweep this one. It gives us a little boost going into the off day. Come out of that and take care of business in Cincinnati."

NOTES: Orioles 3B Manny Machado was held out because of an illness. The timeline for his return is uncertain. ... Red Sox 2B Dustin Pedroia, who left Monday's game in the fourth inning after fouling a ball off his nose, was back in the starting lineup. ... Baltimore LHP Zach Britton might not pitch again this season because of a lingering problem with his left knee. The Orioles plan to further evaluate an MRI to determine if there is any structural damage.