"We've got to do more offensively," manager Scott Servais said. "Our pitching's done a very nice job. I'm happy where we're at, bullpen-wise. We're just not getting it done with the bats right now."
Even an extra inning didn't help. The Mariners wasted a dominant start by Felix Hernandez -- who departed after seven shutout innings -- as the bullpen allowed a pair of solo homers.
The Mariners, whose only run Sunday was unearned, left 10 runners on base and could not capitalize on five walks by Oakland starter Chris Bassitt. In the fourth inning, Bassitt walked the bases loaded, but escaped when Steve Clevenger bounced out to first.
Leonys Martin and Nelson Cruz each had two hits for Seattle on Sunday.
"We just have to be more consistent in our approach," Servais said. "I thought Nelson had some better at-bats today. Leonys found a couple holes, hit the ball the other way, which is a good sign. Top to bottom, it's just a lot of empty outs, is the way I put it."
"We just need to score more runs," said first baseman Adam Lind, who went 0-for-4 to drop his average to .067. "Wednesday afternoon we were pretty happy. Here we are on Sunday afternoon and things aren't quite as happy as they were that day. We have this series against Texas and hopefully we can flip the script."