BOSTON — For one night at Fenway Park, it was 2018 all over again for the Red Sox.

They looked like defending champions against the Yankees, humiliating Masahiro Tanaka in a 19-3 blowout Thursday night. Tanaka allowed a career-high 12 hits and 12 earned runs over 3¹/₃ innings.

This is Boston’s last stand.

“It’s crucial, playing the Yankees, playing Tampa, both teams are ones that we are chasing after,’’ said Red Sox shortstop Xander Bogaerts, who blasted a three-run home run in the first off Tanaka and a solo home run off catcher-turned-pitcher Austin Romine in the eighth.

The Red Sox are in the midst of playing 11 consecutive games against the Yankees and Rays.

“For the most part, it’s the Yankees winning these games this year,’’ Bogaerts said. “It sucks, but this was a good way to start a series. Listen man, we know how good they are, we know they are really good coming from behind. But tonight was a good game.’’

Last year it was the Red Sox who set the pace. This year is much different for the Red Sox, who are 11 games behind the Yankees in the loss column and a game and a half back in the wild-card race.

“We know we’re chasing,’’ Bogaerts said, “so we are just trying to go out there and win as much as possible.’’

Alex Cora is trying to keep his Red Sox focused on the small picture. That is their reality.

“Every series for us is big,’’ the Boston manager explained. “I know where we are at, I know where they’re at. If we win series, we’ll have a great week. … We’ve got to have great weeks the rest of the season. We know where we’re at.’’

With the trade deadline looming, it is either win or be traded.

“That’s a good step,” Cora said of winning two of three against the Rays. “We were coming from a horrible series and bounced back. Now it’s New York, the best team in baseball. Win this series and see where it takes us. Let’s not get too far ahead of ourselves. We know what we have to do. There’s no hiding.’’

Especially at home.

With the win, the Red Sox evened their home record at 25-25. On the road they are 32-22. It all comes back to the pitching. Now more than ever with the livelier baseball.

Overall, the Red Sox are seventh in the AL with a 4.64 ERA, seventh in starter’s ERA (4.71). The bullpen has been a disaster and the numbers show it as they are 10th in the AL with a relievers ERA of 4.59.

At home, the Red Sox are 10th in ERA with an ugly 5.00 mark. They can’t pitch at home.

The Yankees were due for such a collapse after playing a draining three-game series at Target Field against the muscular Twins, but this was even uglier than anyone could have expected. The Red Sox are hoping to gain a little momentum from this win. On Friday the Yankees will send lefty James Paxton out against Andrew Cashner.

Rick Porcello managed to survive through six innings for Boston, surrendering three runs. He wasn’t great, but he didn’t have to be with the offense exploding against Tanaka. After the Yankees scored two in the second and had the bases loaded, Aaron Judge hit a rocket to center that was caught about 410 feet from home to end the inning.

The Red Sox are suffering from a World Series pitching hangover, but there is no doubt Boston can be a dangerous opponent if it makes it to the postseason and past the wild-card game.

Mookie Betts is showing life as the leadoff hitter and has reached base safely in 22 straight games. In Boston’s seven-run first, he led off with a single and then got a second single in the inning, driving in the final two runs of the frame.

The 19 runs were the most the Red Sox scored against the Yankees since 1913. Their last stand is off to a roaring start.