The Red Sox were riding high at the conclusion of their last home stand, having swept the New York Yankees to reach a season-high five-game winning streak.

Then they traded Rafael Devers to the San Francisco Giants and took off without him for their longest road trip of the season.

On Wednesday afternoon, their nine-game west coast swing concluded with a 5-2 loss for a series sweep by the Angels; the Red Sox will return to Boston in a losing skid as long as the winning streak they had when they departed. They averaged only 3.1 runs per game on the trip.

The first inning was promising. Batting second in the Boston lineup, Jarren Duran reached base on an error by shortstop Scott Kingery, and advanced to third when Romy Gonzalez followed with a single. Angels starter Yusei Kikuchi got Carlos Narváez to pop out in foul territory, but walked Wilyer Abreu to load the bases. Trevor Story’s RBI single to left gave Boston an immediate 2-0 lead.

It was all downhill from there, as for the second time in this series, the Red Sox took a multi-run lead in the first and stopped scoring while the Angels came back to tie and overtake them.

Kikuchi was the definition of unyielding in the following innings. He struck out the side in the second and fifth, worked around Narváez’s two-out single in the third, struck out two in a 1-2-3 fourth, and required just six pitches to get the Red Sox in order in the sixth. After throwing 31 pitches in the first inning, he needed no more than 16 pitches in any of his subsequent six frames.

“We’ve seen that game before, and we have to be better offensively,” manager Alex Cora told reporters. “And this happened since early in the season: we score early and then the (opposing) starters hang out ’til the sixth, the seventh, and then they go to the bullpen, and that’s how it works.”

It was Kikuchi’s ninth double-digit strikeout performance of his career, and the fourth time he struck out 12 or more batters. His breaking balls broke the Boston batters, who struck out six times on his slider, three on the curveball, twice on changeups, and only once on his four-seam.

Before Marcelo Mayer’s 321-foot flyout to end the seventh, the Red Sox only had two balls hit further than 200 feet: Gonzalez’s third-inning flyout and first-inning single. Kikuchi retired 19 of his last 20 batters, including the final 13. Through seven innings and 105 pitches (75 strikes), he gave up two unearned runs on three hits, one walk, and struck out 12, one shy of his career-high.

The Red Sox struck out 33 times over this three-game series.

“If you follow us, we’ve been struck out since Day 1,” Cora said. “We have to make adjustments.”

It was a shorter, but promising afternoon for Richard Fitts. Making his first start since being optioned to Triple-A, the newly-recalled Fitts wasn’t able to go as deep into the game as his manager hoped, but his 15 swings-and-misses were a promising sign. (Kikuchi induced 20.)

“I think it was a lot better than the last time I was out there,” Fitts told reporters. “Wasn’t able to extend, innings-wise.”

Over four innings, Fitts allowed two earned runs on four hits, walked one, and struck out six on 83 pitches (58 strikes). In the fourth, his slider became more hittable as it ranged into the heart of the zone, and the Angels capitalized.

Back-to-back homers by Joe Adell and Travis d’Arnaud tied the game. The Angels’ No. 5 and No. 6 batters did the bulk of the damage against Boston, combining for five hits and driving in two runs apiece.

As the Boston bats went quickly and quietly against Kikuchi, the Angels knocked the depleted bullpen around. In the fifth, Luis Guerrero didn’t throw a strike until his eighth pitch, and his 20th pitch was only his sixth strike. For the second inning in a row, Adell and d’Arnaud came through, this time with a pair of two-out singles to give the Angels a decisive lead and knock Guerrero out of the game.

Brennan Bernardino stemmed the bleeding with a first-pitch third out in the fifth, but gave up the Angels’ fifth and final run in the following frame. Zack Kelly and Jorge Alcala combined for the final 2.2 innings; they were the only Red Sox pitchers with scoreless outings, but by then it was already too late.

Facing former Red Sox prospect Ryan Zeferjahn, whom they traded at last summer’s deadline, the Red Sox finally got on base in the eighth. Roman Anthony’s one-out walk was for naught, though, as the rookie right-hander worked around him.

With two outs in the ninth, Story lined one to left and landed on first base, only for a crew chief review to overturn the call. It wasn’t a trap play, Taylor Ward had caught the ball, and the game was over.

After a day off on Thursday, they return to Fenway Park on Friday to host the Toronto Blue Jays and Terry Francona’s Cincinnati Reds for three games apiece.

Yet the sky-high peaks and chasmic valleys that define this Red Sox team were on full display on this road trip. They extended their win streak to six when they won their series opener in Seattle, then were shut out the following night. They’ve lost five in a row after winning eight of their previous nine.

The All-Star break is considered the dividing line between the first and second half of the baseball season, but teams played game No. 81 of 162 this week. More than halfway through their schedule, the Red Sox are 40-42, just as they were in 2023. They were 43-38 through their first 82 games last year.

“We’re not playing great, but we’re not that far off,” Cora said.

Yet every time this Red Sox team pulls closer, they take several steps back.