The Yankees’ Jekyll and Hyde first half ended appropriately.

After opening their series against the Cubs on Friday night with an 11-0 annihilation that marked their fifth straight victory — which came on the heels of a six-game losing streak — the Yankees were flat with the bats for two straight games and skidded into the All-Star break with a 4-1 loss Sunday afternoon in front of 45,435 at the Stadium.

The Yankees (53-43), dominated on Saturday by lefthander Matthew Boyd for eight scoreless innings, had little success against another stud Cubs lefty. Shota Imanaga (6-3, 2.65) allowed one run, two hits and a walk in seven innings in which he struck out six.

“Real efficient. He was ahead of us a lot,” manager Aaron Boone said. “Kind of that back and forth, the change/splitter coupled with locating the fastball. He used them both. Similar to Boyd, [he] did that to us. He’d kind of slow you down and then pop you. Yesterday with Boyd, I thought we were squaring some balls up. Today, not as much.”

After averaging 9.0 runs per game in their previous four games and 7.3 in their previous 12, the Yankees went 6-for-48 with a walk and scored one run in 15 innings against Boyd and Imanaga.

The Yankees, who entered the day two games behind AL East- leading Toronto, were outhit 10-2 by the NL Central-leading Cubs (57-39).

Will Warren allowed a home run by the Cubs' Michael Busch on his second pitch of the day, which portended a grind of an afternoon. He still got into the sixth inning with the score tied at 1-1, but with one on and one out in the sixth and Warren at 88 pitches, Boone called on righthander Ian Hamilton to face Dansby Swanson.

After getting ahead 0-and-1, Hamilton — who had a 1.29 ERA in his previous 16 appearances — hung an inside slider that Swanson roped into the seats in left for his 16th homer and a 3-1 lead. It was only the fourth homer allowed by Hamilton in 35 2/3 innings.

Warren (6-5, 4.63), a 25-year-old rookie who has shown far more good than bad in his first full big-league season, was charged with two runs and allowed six hits and three walks in 5 1/3 innings in his 20th start of the year.

“To be able to get through 5 1/3 against a team like that when I don’t have my best stuff is a positive,” he said. “And so carrying that into the second half and using that when I do have my good stuff to dominate.”

After Busch's  390-foot shot into the Yankees' bullpen for his 19th homer, Giancarlo Stanton led off  the bottom of the second by driving a 2-and-2 splitter to rightfield to tie it at 1-1. It was his fourth homer in his last nine games. But that concluded the highlight portion of Sunday’s program for the Yankees' offense.

Austin Wells led off the sixth with a single, but Oswald Peraza, whose .149 batting average is emblematic of the offensive hole at third base the Yankees have been desperately trying to fill since the winter, popped to second and Paul Goldschmidt grounded into a 5-4-3 double play.

Lefthander Tim Hill struck out Busch and Kyle Tucker to begin the seventh before Seiya Suzuki laced a double to rightfield over Aaron Judge's head. Pete Crow-Armstrong then sent a sharp grounder back up the middle that was fielded by shortstop Anthony Volpe, ranging to his left behind second base. But his throw to first pulled Goldschmidt off the bag and Suzuki, running hard from second off the bat and never letting up, beat Goldschmidt's slightly belated throw to the plate to make it 4-1.

Volpe, who according to rival scouts has slowly regressed in the field this season as his offense has failed to launch, went 0-for-3, extending his most recent slump to 12-for-96 (.125) in his last 27 games.

In the eighth, Volpe didn’t aggressively go after Vidal Brujan’s grounder and Swanson beat his throw to Jazz Chisholm Jr. at second.

“That’s definitely an area I could be better, I expect to be better,” Volpe said of his defense. “The work doesn’t stop.”

Lefthander Max Fried, who left Saturday’s game after three innings because of a blister on his left index finger -— an issue that four times previously in his career has meant an IL stint -— said late Sunday afternoon that it still is “too early” to say whether he’ll be able to start one of the three games in Atlanta after the break. “Definitely feel like it’s getting better,” he said.