BOSTON — The question now isn’t whether or not the Red Sox have taken control of the American League East race.

The question now is whether or not Boston will bury the Yankees once and for all this weekend at Fenway Park, with New York one more loss away from the unthinkable.

Nathan Eovaldi was brilliant for the second straight start and the Red Sox offense provided enough early support to help the right-hander settle in quickly. It all added up to a second straight 4-1 win on another sticky summer afternoon at the ballpark.

This four-game set is on the brink of becoming the Boston Massacre in reverse, the opposite of a Red Sox unraveling while blowing a seemingly insurmountable lead to surrender the A.L. pennant in 1978. The Yankees are the ones about to cry uncle four decades later, with only their recent success against Boston left-hander David Price to rely upon heading into Sunday night’s finale. The Red Sox now enjoy an 8 1/2-game lead, and one more victory will match their largest in the division since September 2013.

“This is a huge series for us,” Eovaldi said. “We’re going to be playing these guys a couple more times on the road, and for us to take the first three games is big in the series.”

“We’ve won the series,” Red Sox manager Alex Cora said. “We’ve got a chance to sweep the series. Whenever we play somebody we’re looking to win the series, and we did already.”

Mitch Moreland’s two-run homer to right in the bottom of the first inning and J.D. Martinez’s solo shot to left in the fourth gave Eovaldi plenty of cushion, as the trade deadline acquisition from the Rays followed up seven scoreless frames against the Twins on Sunday with another gem. Eovaldi’s eight shutout innings made him the first Red Sox starter to post 15 scoreless beginning his career with the club since Billy Rohr in the 1967 Impossible Dream season.

“You look up and he’s throwing 100 (mph) in the eighth inning,” Cora said. “He is who we thought he was going to be. He’s been outstanding.”

New York managed just two baserunners against Eovaldi through the first five innings, both of whom were erased courtesy of double plays. Gleyber Torres bounced into the first and Didi Gregorius grounded into the second, a 4-6-3 twin-killing that left Eovaldi at just 39 pitches through four frames. He finished with 93 in all, tossing 65 for strikes while scattering three hits and striking out four.

“It’s been a lot fun pitching here and playing with these guys behind me,” Eovaldi said. “We’ve been able to score runs early in the game, which makes it a little easier pitching. The defense is amazing.”

Yankees’ right-hander Chance Adams was given the unenviable task of making his big league debut against a club that is transforming into a runaway train atop the division. Adams was rocked early, as Andrew Benintendi singled to center and Moreland drove a hanging breaking ball into the Boston bullpen to make it 2-0. Adams was just 10 pitches into his outing and already on the hook for the loss.

“Got into an advantage count (on 2-and-1),” Moreland said. “Got a breaking ball. It kind of split the plate — maybe a little down — and I was able to get a barrel on it and get it in the air.”

Martinez further cemented the defeat in the fourth, coming to the plate with one out. He smashed an inside fastball from Adams toward the Green Monster in left, peppering the light tower to make it 3-0. It was the 33rd homer of the season for Martinez, who has reached base safely in his last 48 home games.

Eovaldi picked up right where Rick Porcello left off Friday night, as his fellow right-hander needed just 86 pitches and retired the last 21 men in a complete-game 4-1 victory. New York went 12 full innings without placing a runner in scoring position, finally mounting a semblance of a threat when Giancarlo Stanton lined a leadoff double to left in the seventh. Eovaldi retired the next three batters in short order, getting Torres to wave at a slider for an inning-ending strikeout.

“With Rick last night and his performance, I just wanted to try to duplicate that,” Eovaldi said. “Go out there, get the guys back in the dugout as fast as possible and keep them on the ropes.”

Only a high-wire act in the ninth from Craig Kimbrel threatened to spoil this one. The Yankees loaded the bases and brought the go-ahead run to the plate in Greg Bird, who lofted a lazy fly to center to end the threat and the ballgame. New York had to settle for an RBI double to right by Gregorius to break up the shutout bid.