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 Washington at Fenway Park on July 1.

The Red Sox won the 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 won the American League pennant.

This year’s Red Sox streak was the longest in the majors since St. Louis also won 15 straight in September 2021.

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.

Masataka Yoshida had an RBI single for Boston.

The Orioles had a season-high seven-game winning streak halted in the series opener Monday before a rainout Tuesday.

Making his first start after agreeing to a $90 million, five-year contract for 2027-31 on Saturday, the 29-year-old Bradish (7-9) gave up four hits with four strikeouts and a walk.

Three Orioles relievers combined to allow 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.

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.