Cedric Mullins smashed a two-run double during Baltimore’s four-run first inning and drove in two more runs later in the game as the Orioles won their home opener by defeating the Boston Red Sox 8-5 on Monday afternoon.

Tyler O’Neill, who played for Boston last year, racked up four hits and scored two runs in his first home game with the Orioles. Mullins, Ramon Urias, Ryan Mountcastle and Jackson Holliday all added two hits in Baltimore’s 15-hit attack.

Jarren Duran drove in three runs and joined Romy Gonzalez, who doubled in a run in the ninth, and Rob Refsnyder with two hits for the Red Sox.

Serathony Dominguez (1-0), who was the second reliever for Baltimore, was the winning pitcher. Keegan Akin and Yennier Cano each worked an inning of scoreless relief and Felix Baustista allowed two runs in the ninth.

Sean Newcomb (0-1), making his debut for the Red Sox, was tagged for four runs on eight hits and two walks in four innings. He struck out four.

Baltimore starter Cade Povich lasted 4 1/3 innings, giving up three runs on five hits with a pair of walks and eight strikeouts.

The Orioles struck fast in the opening inning. After O’Neill’s run-scoring single, Mountcastle drove in a run with a single and Mullins added the two-out double.

The Red Sox scored on Duran’s two-run triple in the second and pulled closer on Kristian Campbell’s run-scoring groundout in the third.

Heston Kjerstad’s single — his first hit of the season — in the eighth stretched the Orioles’ lead to 5-3. Mullins came through with a two-run single, with the ball reaching the outfield off Boston reliever Cooper Criswell’s foot, and Holliday had a run-scoring single for an 8-3 lead.

Matt Bowman was first out of the Baltimore bullpen with two-thirds of an inning of relief. He pitched Friday night in the season opener for Triple-A Norfolk before he was summoned to the big-league team and then worked out of the bullpen Sunday in Toronto.