The Yankees’ winning streak has reached double digits, and if you ask Aaron Boone for the turning point of their summer swoon, the manager points to J.A. Happ’s outing before the fun began. It had been a complete club effort -- they pitched, they hit, they fielded. For the most part, they haven’t stopped.

Happ kept the good times rolling on Saturday, delivering eight scoreless innings as the Yankees breezed to their 10th consecutive victory, an 8-0 blowout of the Red Sox at Fenway Park. The Yankees’ magic number to clinch a postseason spot is one.

• Box score

“We felt like it was going to turn,” Happ said. “We just needed to keep grinding it out. A 60-game season is a little different, but you hope it balances out. We’re starting to see some guys getting their groove, some guys getting healthy, and becoming the team we feel like we are.”

New York has won all nine games against Boston this year, and 12 straight dating to last season. That equals the Yankees’ longest string of dominance over their rivals; they defeated the Red Sox a dozen times in 1936, and again from August 1952 through April 1953, when Ted Williams was flying combat missions in the Korean War.

“It’s always fun beating those guys,” Boone said. “We obviously respect who they are and all the great games we’ve had to play against them. We’ll enjoy it while it lasts. This is obviously a very unique year, and that rivalry can kick up at any time.”

• Postseason standings

Happ’s turnaround has been nothing short of remarkable. Hit hard in his first two starts, he saw the mound only twice in a 24-day span due to postponements, then confronted Boone and general manager Brian Cashman to express his displeasure about the infrequent nature of his starting assignments.

Since being given the ball on a regular basis, the 37-year-old left-hander has proven that there is plenty left in the tank. Aggressively trusting his fastball while limiting hard contact, Happ held Boston to four hits in a 113-pitch gem, walking none and striking out nine.

“I had some life on the fastball, and the changeup has come around for me,” Happ said. “Lately, it’s been a big pitch. We played good defense, good positioning and were able to get some early outs, which helped me go deeper in the ballgame.”

Over his last five starts -- a span that includes the Sept. 8 effort against the Blue Jays in Buffalo, N.Y., that marked the end of a 5-15 slide -- Happ has pitched to a 1.99 ERA, permitting seven earned runs over 31 2/3 innings, with three walks and 33 strikeouts.

No Yankee has registered a start against the Red Sox with at least eight scoreless innings, no walks and at least nine strikeouts since Mike Mussina’s Sept. 2, 2001, near-perfect game at Fenway Park. Happ’s last such effort was Aug. 5, 2009, when he tossed a shutout for the Phillies over the Rockies.

“He’s obviously going to be on the team [in the postseason] and playing a big role,” Boone said. “This season, he showed me a level of mental toughness and professionalism that has been really admirable. He’s been one of the anchors in the rotation.”

Clint Frazier cracked a two-run homer as part of a three-RBI performance, highlighting the offense as the Yankees took advantage of Boston’s sloppy defense, which included a pair of costly errors by shortstop Xander Bogaerts.

• Frazier spares bug then swats homer

Gio Urshela and Kyle Higashioka collected early RBIs against starter Chris Mazza, as Joe DiMaggio’s distant cousin surrendered four runs (two earned) and five hits over four innings. Luke Voit knocked in a run with a fifth-inning hit, his fifth consecutive game with an RBI.

“We’ve really been able to give our pitchers some run support this last week and a half,” Brett Gardner said. “When you’re playing well, it’s a lot of fun to be a part of.”

Saturday’s victory secured a winning season for the Yanks, their 28th consecutive, and Boone said he would stay up to monitor the Mariners’ outcome in case there was more to toast. Seattle defeated the Padres to keep the Yankees' magic number at one.

“We’ve just been grinding through here, trying to rack up these wins to get to the place that we want,” Boone said. “Now that it’s close to reality, I don’t know quite how we’ll take it in.”