(Photo credit: Daniel Kucin Jr.-Imagn Images)

Josh Naylor smashed a fifth-inning grand slam and the Seattle Mariners held off late-inning threats to beat the host Baltimore Orioles 6-3 to open a four-game series Monday night.

Randy Arozarena rapped three hits and drove in a run and Mariners starter Emerson Hancock worked five strong innings. Hancock (5-2) gave up one run on three hits and two walks and Andres Munoz pitched the ninth for his 10th save, a day after a blown save in Detroit.

Taylor Ward and Blaze Alexander both had two hits for Baltimore, which dropped its third game in a row.

The Orioles had a pregame pitching change when likely starter Chris Bassitt went on the injured list with low back discomfort, resulting in rookie Trey Gibson's call-up from Triple-A Norfolk. Gibson (1-1), in his fourth big-league appearance, was charged with three runs in 4 2/3 innings.

The Mariners, who won for the second time in five games since an eight-game winning streak, trailed 1-0 going to the fifth when they got on the board on Ryan Bliss' sacrifice fly. They then loaded the bases for Naylor's two-out shot off reliever Anthony Nunez for his seventh homer of the year.

The Orioles threatened in the bottom of the seventh, posting a run on Matt Brash's wild pitch. Gunnar Henderson recovered from a 0-2 count to work a walk and then Brash's first three pitches to Pete Alonso were balls before a full-count pitch. Brash's delivery was initially ruled a ball, but the Mariners had a successful challenge so Alonso went down for the second out of the inning before Brash escaped when Colton Cowser grounded out.

In the eighth, Naylor's infield single and a wild pitch put him in position for Arozarena's run-scoring single.

Baltimore countered when Alexander singled to drive in a run but a double play ended the inning. Samuel Basallo's would-be pinch-hit sacrifice fly was wiped out when Alexander was thrown out trying to advance to second base. The out was recorded before Jackson Holliday, who began at third base, reached the plate.

--Field Level Media