The Rays' lead was cut to two games over the Cleveland Indians and Baltimore Orioles in the race for the second wild-card berth in the American League.
After tying the game in the top of the eighth, the Rays couldn't keep the Mariners from going ahead.
Kyle Seager hit a fly ball off Peralta (2-6) deep into the gap in left-center.
Though center fielder Desmond Jennings got in position for the play, the ball caromed off the heel of his glove and fell to the turf allowing Seager to reach second base on the error.
Kendrys Morales walked before Smoak's fly down the right field line just missed the glove of a diving Wil Myers. Seager and pinch runner Abraham Almonte scored to give the Mariners a 6-4 lead.
Carter Capps (3-3) picked up the victory in relief.
Danny Farquhar pitched a scoreless ninth to earn his 13th save.
Brad Miller doubled to lead off the game for Seattle and scored on a sacrifice fly by Seager to the Mariners a 1-0 lead.
The Rays tied it in the second inning. Delmon Young crushed a solo home run off Mariners starter Hisashi Iwakuma to left-center field.
Ben Zobrist and Evan Longoria each singled with two outs in the third inning and Matt Joyce drew a walk to load the bases.
A wild pitch allowed Zobrist to score from third to give Tampa Bay a 2-1 lead. Iwakuma managed to work out of the jam by getting Young to ground out to second to end the inning.
Seattle retook the lead in the bottom half of the inning. Nick Franklin reached on a fielder's choice and stole second base.
Franklin Gutierrez singled up the middle past the outstretched gloves of Alex Cobb to drive in Franklin and tie it. Gutierrez added a stolen base to get into scoring position for Seager, who delivered an RBI single to give the Mariners a 3-2 lead.
Raul Ibanez hit his 27th home run off Cobb to lead off the fourth inning and extend the Mariners' lead.
Cobb allowed four runs and seven hits in six innings for Tampa Bay. He struck out five and walked one.
The Rays closed the gap in the sixth inning. Young doubled and the Mariners elected to walk Myers to bring Jose Molina to the plate. Molina answered with a single that scored Young and chased Iwakuma from the game.
Iwakuma allowed three runs and eight hits with five strikeouts over 5 2-3 innings for Seattle.
A base running mistake cost the Rays a chance to take the lead in the eighth inning. James Loney drew a leadoff walk and Myers followed with a single.
Sean Rodriguez came on to pinch run for Loney, but was picked off by Capps at second. The mistake cost Tampa Bay a run as Luke Scott doubled to left-center field to score Myers from first.
Capps walked Jennings and Zobrist to load the bases, but induced a ground out from Longoria to get out of the jam and keep the game tied at 4-4.
Tampa Bay manager Joe Maddon said the Rays rotation for their upcoming series with the Boston Red Sox will consist of David Price, Alex Cobb and Jeremy Hellickson. Both Hellickson and Chris Archer will get an extra day of rest before their next start. Archer will start against Minnesota. ... Raul Ibanez is just the third player in major league history to hit at least 27 home runs in a season at 41 years of age or older. Only Ted Williams (29 home runs, 41 years old) and Barry Bonds (28 home runs, 42 years old) have hit more.