BALTIMORE—When the Orioles began their season with a three-game sweep of the Boston Red Sox last weekend, hopes were heightened that perhaps this Orioles team was better than many had forecast.

Since then, the Orioles have lost five of six, including three straight this weekend to the Boston Red Sox. They’ve slipped below .500 at 4-5.

Sunday’s 14-9 loss to the Red Sox before 8,171 at Oriole Park was particularly difficult because Boston isn’t expected to contend this season. Oriole pitching allowed six home runs, three to J.D. Martinez, two to Rafael Devers and another to Alex Verdugo.

In the season-opening series, the Orioles held Boston to five runs. This weekend, they scored 27.

“They’re swinging the bats better right now,” manager Brandon Hyde said. “They’ve got some guys that are really hot. J.D. is obviously on fire.”

Martinez added an RBI single to his three solo home runs, and is hitting .472 with a 1.583 OPS.

In Thursday’s home opener, the Orioles lost, 7-3, and dropped a 6-4 game in 10 innings on Saturday night.

“In the first game, we had a lead the first part of the game, couldn’t put up zeros the second half of that game. I thought we were two outs away from winning last night,” Hyde said. “Today, it just got away from us.”

Orioles starter Jorge López gave up four runs in the third inning. After Franchy Cordero and Kiké Hernández began the inning with singles, Verdugo hit a three-run home run. Martinez, who was put on the injured list on Saturday because of Covid-19 symptoms, homered in his return.

“He’s a really good hitter,” López said. “We all know that. Every hitter they have has a good, good approach, good at-bats. Those power guys, you’ve got to keep them guessing.

“He was hot today, he got the barrel on everything, and he’s a guy you have to execute good pitches to.”

The Orioles had a chance to score in the bottom of the third. With one out, shortstopFreddy Galvis singled, centerfielder Cedric Mullins singled to extend his hitting streak to nine games, and first baseman Trey Mancini’s grounder bounced off Boston first baseman Bobby Dalbec’s glove for an error to load the bases.

Rightfielder Anthony Santander, who strangely sacrificed with one out and Mancini on first in the first, took a called third strike after fouling off seven of eight pitches.

With designated hitter Ryan Mountcastle at-bat, Red Sox starter Nick Pivetta’s pitch got away from catcher Christian Vazquez, and Galvis attempted to score. Pivetta somehow got to the plate in time, blocked Galvis’ path, and he was thrown out to end the inning.

In the bottom of the fourth, Mountcastle doubled, and with one out, third baseman Maikel Franco’s single scored Mountcastle. Rio Ruiz’s inning-ending double play halted the rally.

Boston quickly ended López’s day. Martinez’s RBI single, the third in a row to begin the fifth, made it 5-1, and Mac Sceroler replaced López.

Sceroler’s second batter, Devers, hit a three-run home run. He homered in each of the three games this weekend.

Martinez homered, his second of the game, leading off the sixth.

Ryan McKenna, batting for Santander, hit a triple off the center field wall for his first major league hit to start the bottom of the sixth. With one out, DJ Stewart walked, and Franco lined a three-run home run, his first homer as an Oriole.

“My first ever hit in professional baseball was a triple,” McKenna said. “A really similar hit. I was thinking the other day, ‘that would be pretty cool if that happened.’ It ended up being a good swing, and Camden’s a deep park in center field. It’s got some real estate out there. I was taking note of that and making sure I was hustling, and I was trying to look for an extra-base hit if I could drive something there.”

Pivetta allowed four runs on seven hits in six innings.

Austin Brice replaced Pivetta for the seventh and, after walking Ramón Urías, who replaced Galvis at shortstop, and Mullins, Mancini hit a three-run home run to right field to close the gap to 10-7. Mancini also homered in Saturday night’s game.

Martinez hit his third home run of the game against Tyler Wells in the eighth, and Devers hit his fourth homer of the series, and second of game, off Shawn Armstrong, a two-run shot, also in the eighth, and the Orioles trailed, 13-7.

Boston’s final run scored when Ruiz and then Urias muffed Cordero’s grounder. Urias then recovered the ball and made an ill-advised throw home that was nowhere near the plate. Marwin Gonzalez, who wasn’t running, scored easily.

In the ninth, Mullins, who had another two-hit game, doubled and eventually scored on an infield out by Mancini. McKenna singled and scored on a wild pitch.

Notes: Mullins has a .459 average and a 1.188 OPS. Dating back to last season, Mullins has a 13-game hitting streak.