– There’s a belief that when the summer winds pick up, the Cubs offense takes off.

And when the Twins entered the Friendly Confines of Wrigley Field on Friday, they noticed that the flags were flying straight out to center field.

“Just playing here, seeing how the it was carrying in B.P., seeing the home runs that were hit,” Twins outfielder Robbie Grossman said. “When the wind blows out, it’s pretty self-explanatory.”

When the wind blows out at Wrigley, you better get in character. Pitchers try to keep the ball down while hitters look to elevate them — especially in the launch-angle age.

The Twins must have missed the text message.

Five home runs later — four struck by the home team — the Twins lost 10-6 in the opener of their interleague series against the Cubs.

Joe Mauer drove in five runs for the Twins, including a three-run homer in the second that was kissed by wind until it dropped into the basket in left-center. The game turned in the fifth when Addison Russell hit a grand slam off Jose Berrios, a towering drive that floated and floated until it left the park.

“I’ve been here and have seen both sides of it,” Twins manager Paul Molitor said. “Today, pretty high-end extreme of favorable to the offensive side. It played a little of a role in the game. We got a little bit of a boost on Joe’s ball and on the grand slam. That one was a mile high and it just seemed to really have a lot of carry.”

Wrigley was set up to be a launching pad Friday, but the Twins struck just one homer in their first game there since 2009.

Mauer, with runners on first and third in the second inning, got hold of a Mike Montgomery pitch and hit a three-run homer. It was a flashback moment for Mauer, who in 2009 hit a two-run home run to left-center in his second at-bat.

Jason Heyward pulled the Cubs within 3-2 in the third with a two-run shot to right. The Twins knew they needed to keep scoring.

“Especially with that lineup they have,” Mauer said. “That’s a good ballclub. I looked over to Dozier throughout the game and said it’s going to be one of those offensive games. They put some runs on the board.”

Mauer batted with runners on second and third in the fourth inning and struck a liner to center that Albert Almora Jr. raced to his left to catch, but it ticked off his glove for a two-run double. It was Mauer’s first five-RBI game since last Sept. 17. And the thousands of Twins fans among the announced crowd of 41,492 roared.

But Berrios’ command was spotty, especially with his curveball, leading to him giving up six earned runs, his most this season. And he hung that pitch to Russell in the fifth with the bases loaded. Russell blasted it to left, and outfielder Eddie Rosario kept backing up until he was out of room. The Cubs led 6-5.

“I hung the curveball right in the middle,” Berrios said. “He hit it up and I think it was the wind pushed it out. It wasn’t like he hit it really hard.”

Ben Zobrist, with a two-run blast, and Kyle Schwarber, with a solo shot, added home runs off the Twins bullpen as the Cubs pulled away in their opener of a nine-game homestand.

“Even at 6-5 you’re thinking we’re going to score some more and get back in the game,” Molitor said. “But we couldn’t hold them down on the back end.”