Warwick Saupold (2-1) got the victory and Shane Greene pitched the ninth for his 10th save as the Tigers won at Safeco Field for the first time in eight games.
Mariners right-hander Nick Vincent (1-1) entered in the eighth but couldn't make it through the inning.
With one out, Victor Martinez singled to left and was replaced by pinch runner Victor Reyes. After John Hicks was caught looking at a called third strike, Mikie Mahtook grounded a single to right field, sending Reyes to second. A walk to James McCann loaded the bases. Iglesias grounded a two-run single to center field to give the Tigers their first lead.
Detroit left-hander Matthew Boyd, who grew up just outside Seattle and was making his first start in his hometown, pitched six strong innings.
Boyd, who was named the Washington state co-player of the year while at Eastside Catholic High School in Sammamish, allowed two runs on six hits with one walk and a career-high nine strikeouts.
The Mariners opened the scoring in the second inning as Kyle Seager led off with a double to right field. With two outs, Guillermo Heredia lined a single to left field to score Seager.
In the third, Jean Segura led off with a double to left and scored on Mitch Haniger's single to center, making it 2-0.
Seattle left-hander Marco Gonzales pitched 5 2/3 innings, allowing only an unearned run on five hits. He walked one and fanned two.
With two outs in the sixth, Hicks walked and Mahtook grounded a single into center. Gonzales got McCann to hit a chopper down the third base line that Seager fielded easily, but his one-hop throw to first skipped off the edge of the infield grass and under the glove of first baseman Ryon Healy. The throwing error allowed Hicks to scored and left runners at second and third.
Right-hander Ryan Cook, making his Mariners debut after being called up earlier in the day from Triple-A Tacoma, struck out Jose Iglesias on three consecutive pitches to end the inning and preserve a 2-1 lead.
It stayed that way until the Tigers' winning rally in the eighth.
--Field Level Media