Martinez knocked in the go-ahead run with a double in the seventh inning, capping a two-run rally.
Torii Hunter went 2-for-5 with a solo home run and two runs scored and Prince Fielder was 3-for-4 with two doubles, one RBI and scored two runs.
Tigers starter Doug Fister (13-9) pitched well enough through 7 2/3 innings, despite four runs given up. He struck out 10 and allowed one walk and one home run. The save was collected by Joaquin Benoit, his 22nd of season. He notched one strikeout in a perfect ninth.
"Our defense really picked me up a lot of times tonight," Fister said. "And the offense just kept grinding until it took its toll on the other team."
The Mariners' Dustin Ackley was 1-for-5 with a three-run home run. Raul Ibanez went 1-for-4 and added an RBI.
Seattle starter James Paxton lasted five innings and gave up three runs, struck out three and walked four. He left the game with the lead, but got a no-decision.
Reliever Charlie Furbish (2-6) picked up the loss for Seattle after allowing one run in his one inning of work.
In the seventh inning Hunter led off with a double and Miguel Cabrera flew out to right to send Hunter to third. Fielder singled to center to score Hunter. Martinez then hit his second double of the game, scoring Fielder for the decisive run of the game.
Earlier, Kyle Seager had a two-out single in the first inning followed by a Kendrys Morales single which set up Ibanez's single to drive in the first run of the game, giving Seattle a 1-0 lead.
The Tigers answered in the bottom of the first when Hunter hit a solo home run with one out. After the home run Cabrera walked and Fielder hit into a fielder's choice to second. Martinez then drove in Fielder from first with a double into left field to make the score 2-1.
In the bottom of the third, Paxton walked Omar Infante with the bases loaded to force in another Detroit run.
In the top of the fifth Fister ran into trouble, giving up singles to Mike Zunino and Carlos Triunfel. Ackley then hit a three-run homer, his fourth of the season, to give Seattle the lead at 4-3.
"I thought we did a good job of making (Fister) work," Seattle manager Eric Wedge said.
The Tigers are five wins from clinching the AL central ... Detroit raised its single-season strikeout record to 1,322 ... Tigers pitchers had 45 strikeouts in the four-game set ... Detroit took the season series 5-2 ... Ibanez still remains one home run away from having 300 for his career and from tying Ted Williams for most home runs in a season by a player over 40 years old ... Tigers left-handed reliever Phil Coke was unavailable due to tenderness in his elbow.
09/19 19:44:47 ET