BOSTON -- Domingo Germán strutted off the mound after a dominant seventh inning, having protected a bid for history with a four-strikeout inning against the heart of the Red Sox's lineup. His pitches were crisp, his performance was electric and he knew exactly what was in the hit column.

By the end of the eighth, Germán was hanging his head in the visiting dugout alongside the rest of his teammates. Germán surrendered a loud double, then had to watch as the Red Sox rallied for five runs, dealing the Yankees a 5-4 defeat Sunday that immediately ranked among the club's worst losses of their season.

"It's like you find yourself on top of the world, and all of a sudden, you're free falling," Germán said through an interpreter. "You fall fast. It's so hard to even process -- like, 'What happened? How did it happen?' It's hard to even analyze everything that goes on. It's extremely tough."

German's 93rd pitch was scorched to deep right field by Alex Verdugo, soaring over Greg Allen's head and bouncing against the Red Sox's bullpen wall. That prompted a call to the bullpen for Jonathan Loaisiga, who surrendered hits to all four batters he faced, with Hunter Renfroe, Christian Vázquez and Kiké Hernández drilling run-scoring knocks.

Pinch-hitter Kevin Plawecki greeted Zack Britton with a game-tying groundout, and Xander Bogaerts' sacrifice fly put Boston ahead. Matt Barnes closed out the ninth around Giancarlo Stanton's two-out single, sealing the Yanks' third loss in four games this weekend and their 10th defeat in 13 tries vs. Boston overall.

"I wasn't able to locate my slider for strikes and my sinker wasn't moving," Loaisiga said through an interpreter. "It's been a very important pitch for me the whole season, and unfortunately today it didn't have the action that it's had in the past. It's a bad day for me. It hurts."

Rougned Odor homered and drove in two runs as New York touched left-hander Martín Pérez for three runs over six innings. Gio Urshela went 1-for-3 with an RBI single in his return from the COVID-19 injured list, and Gleyber Torres drove in a run in the eighth that built a four-run Yankees lead at the time.

The collapse marked yet another "gut punch," to borrow from manager Aaron Boone's parlance, in a season that has been defined by them.

Another came in Thursday's series opener, with Chad Green blowing a two-run lead with two outs in the ninth -- other hard-to-swallow recent defeats have included heartbreakers against the Angels (June 30), Mets (July 4) and Astros (July 11).

"Especially over the last month and a half, we've had some really tough ones that we've had to get past," Boone said. "Time and time again, these guys have done it and continue to reveal their character. It's been a difficult season to this point, no question about it. But to these guys' credit, they continue to get off the mat."

Seven strong
Through seven innings, Germán had the Red Sox flailing, generating 18 swings and misses while leaning heavily upon his curveball (35.5%) and four-seamer (32.3%). A third-inning walk to Renfroe marked Boston's only baserunner until the seventh, when Xander Bogaerts struck out and reached first base on a passed ball, an apparent cross-up with catcher Gary Sánchez.

Germán recovered, fanning Rafael Devers and J.D. Martinez to keep the bid alive, becoming the fourth player in franchise history -- and second this season -- to record a four-strikeout inning. A.J. Burnett (2011) and Phil Hughes ('12) achieved the feat previously, and Loaisiga did it on June 25 at Fenway.

"Unfortunately, I couldn't finish what I really wanted there, which was to go all the way," Germán said. "I was missing a start like this one, to get me back on track after a few outings where it's been tough just getting to the fifth inning. It's definitely satisfying; it gives you confidence."

Yankees starters combined to hold the Red Sox to five earned runs over 24 2/3 innings (1.82 ERA) over the weekend set.

"Domingo pitched a tremendous game and put us in a great position," Boone said.

Jonny on the spot
Loaisiga threw 18 pitches in a scoreless inning in Saturday's 4-3 Yankees win, marking his return from the COVID-19 injured list, and the right-hander said that he felt strong pitching on back-to-back days for the first time since June 1-2.

The results didn't follow. With Britton warming, Boone hesitated to pull Loaisiga after the third Boston hit, saying that he liked the matchup. Hernández smoked a 2-0 sinker for a run-scoring double, at which point the pitching change was made. Boone said that it was "a fair question" why Loaisiga hadn't been lifted.

For Plawecki's at-bat, the Yankees had the infield in at the corners and back in the middle. Boone said that he didn't want to be beaten by a soft hit, a decision that he questioned in hindsight.

"We were set up at the back end," Boone said. "We just didn't get it done."