Snell held the Mariners scoreless on two hits and two walks while striking out eight in seven innings en route to his second win of the season.
The Rays' struggling offense showed life on Sunday, with Kevin Kiermaier leading the parade with a home run to start the bottom of the first. Kiermaier's eighth home run off the season came on a 2-0 fastball from Mariners starter Yovani Gallardo and cleared the wall in center.
"I just wanted to start the game off with a bang in any way you can," Kiermaier said.