PHOENIX -- The Red Sox’s nine-game, three-city road trip came to an end on Sunday afternoon with a 4-2 loss to the D-backs under the roof at Chase Field.

Boston left with a series win, but went 4-5 on the road trip. The team will fly back home and enjoy an off-day on Memorial Day -- good timing with the Celtics playing at home in Game 7 of the NBA Eastern Conference Final -- before a weeklong homestand that starts Tuesday against the Reds.

There are some areas the Red Sox excelled at in Phoenix and others that still need improvement, which will be critical with the Rays coming into town next weekend for a four-game series.

Here are three takeaways from this weekend’s series in the desert:

The bullpen anchored

Let’s start with a positive note. Red Sox manager Alex Cora has emphasized how happy he is with the state of his pitching staff, especially the bullpen.

Through 12 innings, the 'pen only allowed one run and kept the Red Sox within striking distance. In Saturday’s win, the relief corps worked four innings with just a one-run difference, which was highlighted by an athletic play by Kutter Crawford that resulted in a right ankle contusion -- Cora said Crawford is OK and should be available in Tuesday’s series opener.

Sunday was the same tale. After taking over for Tanner Houck in the fifth inning with a four-run deficit, the bullpen kept the D-backs’ bats quiet. Cora said pregame that Nick Pivetta, who was moved to the bullpen after a win over the Mariners on May 17, would be relied on heavily in the series finale, and he delivered with three scoreless innings.

“That's what we envisioned,” Cora said. “The breaking ball was good. He kept on balance, but the velocity was a lot better and that's what we want. We want him to pace himself. … He's done it before with us and he was good. So hopefully today was the first step for something great for him.”

The offense needs to show up more consistently

Friday’s offensive outburst (seven runs on 14 hits) was a good sign, especially coming off a four-game losing streak, but after that, they were not clutch with runners in scoring position.

Saturday’s game-winning play came on a self-called bases-loaded sacrifice bunt by Reese McGuire. It was a play that luckily paid off, but the Red Sox shouldn’t have had to rely on that run considering they left seven runners on base that game.

The same struggles continued on Sunday, except this time the Red Sox left 10 runners on base. After struggling against D-backs starter Merrill Kelly, the offense woke up in the last three innings, each time with runners in scoring position. They only capitalized once, on a bases-loaded RBI single by Alex Verdugo in the seventh inning.

Rafael Devers made his return to the lineup and played third after missing back-to-back games with left calf tightness. He had two chances to change the outcome of the game, most notably with the bases loaded in the seventh inning when he struck out on a two-out pitch out of the zone by Andrew Chafin. He was visibly frustrated after ending the inning.

“Everybody wants to do their job when there's bases loaded,” Devers said through an interpreter. “You always want to help your team win and get some runs in. I think it was a bad pitch and I got a little frustrated over that but nothing special.”

Houck’s start a tale of adaption

Houck was looking to build off his solid start against the Angels. Instead, he gave up three runs in the first inning, which was led by a two-run opposite-field homer from Corbin Carroll. Houck finished by giving up four runs on six hits over four frames, his shortest outing of the month.

Houck answered by retiring every batter the second time through the order. The key to calming down? Looking at the film with Red Sox pitching coach Dave Bush and making in-game adjustments.

“[The] sinker, slider, kind of everything was just flat,” Houck said. “I know whenever I get to planes, horizontal and depth, pitches are a lot better. So it's one of those things where it's getting too much on the side of the ball as well as rotational, causing things to flatten up just a little bit.”