BALTIMORE (Interstat) — Josh Naylor hit a grand slam in the fifth inning Monday night, powering the Seattle Mariners to a 6-3 victory over the Baltimore Orioles at Oriole Park at Camden Yards.

Naylor’s seventh home run of the season capped a five-run outburst in the fifth that broke open a 1-0 game and sent Seattle to its second straight win. The Mariners improved to 35-32, while the Orioles fell to 31-36.

Seattle struck first in the top of the fifth against Baltimore starter Trey Gibson. Dominic Canzone led off with a single, and after a flyout, Jhonny Pereda singled to put runners at the corners. Ryan Bliss then lifted a sacrifice fly to center, scoring Canzone for a 1-0 lead. Cole Young followed with a single, Julio Rodríguez walked to load the bases, and Naylor crushed a 1-0 pitch over the right-field wall, clearing the bases and giving the Mariners a 6-0 advantage.

Baltimore got on the board in the third inning. Blaze Alexander was hit by a pitch, moved to second on a walk to Taylor Ward and to third on a walk to Gunnar Henderson. Pete Alonso’s sacrifice fly to center plated Alexander, making it 1-0 at that point.

The Orioles chipped away in the seventh. With two outs and runners on second and third after a single by Alexander and a groundout, Ward was hit by a pitch to force in a run, cutting Seattle’s lead to 6-2. Henderson walked to load the bases, but Pete Alonso was called out on strikes after a replay review, ending the inning.

In the eighth, Seattle added an insurance run. Josh Naylor singled with one out, and Randy Arozarena followed with a single to right that scored Naylor, making it 6-2.

Baltimore countered in the bottom of the eighth. Leody Taveras led off with a single, Jackson Holliday walked, and after a flyout, Alexander singled to left to score Taveras and cut the deficit to 6-3. But Samuel Basallo, pinch-hitting, flied into a double play as Alexander was retired at second on a relay from center fielder Julio Rodríguez.

The Orioles threatened again in the ninth against Seattle closer Andrés Muñoz. Henderson walked with one out, but Pete Alonso struck out swinging and Colton Cowser struck out swinging to end the game. Muñoz earned his 10th save of the season.

Seattle starter Emerson Hancock pitched 5 2/3 innings, allowing one run on four hits while striking out three and walking two. He improved to 5-2. Cooper Criswell worked 1 1/3 innings of relief, allowing two runs on two hits, and Muñoz closed it out.

Gibson took the loss, falling to 1-1. He gave up two runs on three hits over 3 2/3 innings, with one walk and one strikeout. Anthony Núñez allowed the grand slam and two earned runs on one hit in 2 1/3 innings, striking out two. Albert Suárez threw two innings of relief, surrendering one run on three hits with three strikeouts.

Offensively, Seattle collected nine hits. Naylor went 2-for-5 with the grand slam and four RBIs. Arozarena had three hits, scoring once and driving in one. Canzone added a double and a single. Young singled and scored a run. Pereda had two hits and scored once.

Baltimore managed six hits. Taylor Ward went 2-for-3 with a walk and a hit-by-pitch. Blaze Alexander was 2-for-3 with a hit-by-pitch, two RBIs and a run scored. Henderson walked three times and singled. Taveras had a hit and a run. The Orioles left 11 runners on base.

The game took 2 hours, 45 minutes before an announced crowd of 12,377.

Seattle continues its series in Baltimore on Tuesday, with the teams playing three more games at Camden Yards before the Mariners visit Washington and the Orioles host San Diego. The clubs will meet again in Seattle later this month.

Interstat’s game simulator had projected a final score of Seattle 7, Baltimore 6. Interstat’s ELO system gave Seattle a 53.60 percent probability to win. Seattle was installed as a pregame favorite with a spread of minus-1.5. The total of nine runs went under the over-under line of 8.5.