BOSTON -- The Baltimore Orioles ended Boston's franchise-record-tying 15-game winning streak behind Kyle Bradish's six innings of one-run ball, defeating the Red Sox 5-1 in the nightcap of a doubleheader Wednesday.
It was Boston's first loss since a 10-2 setback to the Washington Nationals at Fenway Park on July 1.
The Red Sox won Wednesday's opener 6-3 to match the club's 80-year-old record. Boston's 1946 team that won 15 straight was led by Ted Williams and claimed the American League pennant.
"That was a great ride, a 15-game winning streak," Boston first baseman Willson Contreras said in a quiet clubhouse after the loss. "There's nothing to be sad about. We have to be happy. We should be proud of what we did and from now keep playing the way we've been playing."
This year's Red Sox streak was the longest in the majors since the St. Louis Cardinals also won 15 straight in September 2021.
After the defeat, Boston interim manager Chad Tracy was ready to speak to the team but saw Contreras and pitcher Sonny Gray talking, so Tracy let those veterans handle it.
"We just won 15 games in a row, and I think all of us knew it was going to end at some point," Tracy said.
The Red Sox had seemed to be in for a long season under Tracy after firing manager Alex Cora following a 10-17 start. They were 37-48 and last in the AL East on July 1 following the loss to Washington.
But three weeks went by -- a stretch including the All-Star break -- before Boston (52-49) lost again.
Tracy is the first manager since the 19th century to lead a team to a win streak of 15 games or more who didn't start the season in the role, according to MLB.
In the nightcap, Dylan Beavers had a two-run single in a four-run first inning for Baltimore, which avoided a three-game sweep and won for the 11th time in 16 games. The Orioles had a season-high seven-game winning streak halted in the series opener Monday, before a rainout Tuesday.
Masataka Yoshida had an RBI single for Boston.
Making his first start after agreeing Saturday to a five-year, $90 million contract through 2031, the 29-year-old Bradish (7-9) gave up four hits with four strikeouts and a walk. Three Orioles relievers combined to give up one hit.
After the Red Sox took a 4-0 lead in the day game, Baltimore knocked out Eduardo Rivera (0-1), who retired only two batters, with its four runs in the first.
The first run came in on Rivera's wild pitch. After Beavers made it 3-0 with his single, he scored on Johnathan Rodriguez's double off the Green Monster.
The Associated Press contributed to this report.