BOSTON -- There are not many people who predicted at the start of the season that the New York Yankees would be in first place at the All-Star break.

But Friday night's 5-1 win over the rival Boston Red Sox assured that will in fact be the case.

"This group has a good feel to it," Alex Rodriguez said after his solo homer and bases-loaded walk allowed the Yankees to maintain their three-game division lead with two to play before the break. "It's a hard-working group. It competes hard every night and I think the key for us finishing up the first half and also continuing into the second half is to stay hungry and humble."

The designated hitter walloped a towering home run completely out of Fenway Park in the first inning and then capped a break-filled three-run fourth -- that included Boston starter Clay Buchholz leaving with an elbow problem -- with his walk.

Ahead 1-0, the Yankees had runners at second and third and one out in the fourth when Buchholz left with tightness in high right elbow. The Red Sox were then guilty of three straight infield miscues, two of them by first baseman Mike Napoli, and Rodriguez capped the rally with his walk.

From there, right-hander Michael Pineda and the bullpen took over as the Yankees (47-39) won their third straight and ended Boston's four-game winning streak.

"I think it's big," New York manager Joe Girardi said of winning the opener against a team that had cut a 10-game deficit in half by Wednesday in a division most consider wide open. "You come in here and you try and win a series and it gives you a chance to win a series here."

Pineda (9-5) went 6 2/3 solid innings, allowing only a solo homer to center fielder Mookie Betts, in the fifth inning. Left-hander Justin Wilson, righty Dellin Betances and lefty Andrew Miller finished up with 2 1/3 innings of hitless relief -- picking up five strikeouts on seven outs.

Left fielder Brett Gardner, named to the All-Star team Thursday, had a hustle RBI single and center fielder Jacoby Ellsbury also drove in a run with a single as the Yankees beat their rivals for the fifth time in seven games this season.

After the game, Girardi said the Yankees are bringing up second base prospect Rob Refsnyder and that the kid will be in the lineup against a pair of left-handers in the two games left before the break.

Buchholz (7-7) had been 4-0 with an 0.87 ERA in his four previous starts and owned a five-game winning streak. The right-hander has had a history of injuries.

"Nothing anything more than what has been announced," Boston manager John Farrell said when asked about Buchholz after the game. "There's some tightness, some stiffness in the elbow area.

"He's undergoing a full work up with imaging, so until we get any further information that's all we have right now."

Rodriguez, 1-for-14 coming in and coming off a 4-for-20 homestand, hit his 17th homer of the season all the way out of Fenway Park -- the 671st of his career. It was also his 12th hit and third homer in 28 career at-bats against Buchholz, Rodriguez saying, "Sometimes numbers can be deceiving -- I can't say that I feel that (good) up there (against him)."

On the Yankees' first 2015 visit to Fenway in May, Rodriguez drilled a bullet that got over the Green Monster in the blink of an eye. This time, his homer was far more majestic, leaving the park entirely.

Yankees shortstop Didi Gregorius, whose double was a key in the fourth inning, hit a fan in the head with a foul ball in the fifth inning. The fan, a young woman, was clearly cut but was able to walk out under her own power. Gregorius sent out a bat as a gift.

NOTES: Yankees 3B Chase Headley missed his third straight game with a calf injury. He said he was ready, but it appeared he would sit out the rest of the weekend. ... Boston 2B Dustin Pedroia, on the disabled list with a hamstring strain, is also likely to sit out and get the extra All-Star break rest. ... Slumping Red Sox 1B Mike Napoli was back in the lineup after sitting for three games. "We're going to need his production and tonight is an opportunity for him to get back on track," manager John Farrell said before the game. Napoli went 1-for-3 and was hit by a pitch, but was also guilty of poor fielding. ... RHP Ivan Nova pitches for the Yankees against rookie LHP Eduardo Rodriguez in Saturday night's second game of the series. ... Red Sox C Blake Swihart (foot) began a rehab assignment as the DH for Triple-A Pawtucket on Friday night.