Hernandez, the team's Opening Day pitcher, allowed one run on three hits over four innings with one walk and four strikeouts.
"They jumped on him early in the count, guys have been very aggressive. His stuff was good again," said Mariners manager Scott Servais. "He's a battler, he's a competitor and he doesn't want to give up runs in Spring Training. I thought his stuff was really good."
Seattle's Efren Navarro knocked in two runs, one coming on a home run to right field in the fourth inning.
Arizona starting pitcher Tyler Wagner, who is trying to win a spot at the back end of the team's rotation, allowed two runs on five hits in five innings. He walked one and had four strikeouts.
Arizona leadoff hitter Socrates Brito had two hits, including a triple. Ed Lucas had two hits for the Mariners.
Up next for D-backs: Shelby Miller gets the starting nod for the D-backs on Sunday at 1:05 p.m. MST, live on Gameday Audio, against the Reds in Goodyear, Ariz. It will be the right-hander's third Cactus League appearance. His last outing came in a camp game during Tuesday's off-day.
Up next for Mariners: The Mariners face the Indians on Sunday at 1:10 p.m. PT at the Peoria Sports Complex as Wade Miley makes this third start of the spring. Miley has allowed three earned runs in his first four innings this spring. He allowed three runs in three innings the last time out to the Cubs. Closer Steve Cishek is also scheduled to pitch. He hasn't allowed a run in three innings. The game will air on MLB.TV and Gameday Audio.
Corey Brock is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.