The youngest starting pitcher to take the mound for Detroit in almost 30 years, the 20-year-old Porcello looked more like a seasoned veteran shutting down Seattle's offense.

He didn't allow a base runner after Ichiro Suzuki's infield single with one out in the third and gave up one run and five hits. Porcello (1-1) struck out three and didn't issue a walk.

Leading 5-1, Santiago provided some cushion in the eighth with a three-run double that barely eluded the glove of left fielder Endy Chavez. His previous career high was four RBI against Toronto in 2003.

But while Santiago's offense was an unexpected boost, the key for Detroit was its young right-hander. Porcello experienced some rookie bumps in his first start on April 9 against Toronto, lasting five innings and giving up nine hits.

He learned from that initial experience, mixing his pitches to keep Seattle hitters off balance. Only once, in the second inning, did Porcello have two base runners on, but quickly erased that scoring chance for Seattle with an inning-ending double play.

When Porcello began to tire in the seventh he got help from Brandon Inge with a brilliant diving stab off an Adrian Beltre line drive, and two batters later, added a leaping grab off Yuniesky Betancourt's bat. Before the game, Tigers manager Jim Leyland expected to keep Porcello under 100 pitches; he threw 86 in his seven innings.

Carlos Silva was inconsistent again for the Mariners. After throwing seven solid innings in Seattle's home opener last Tuesday, Silva (0-2) barely made it through five innings against the Tigers, a team he struggled against last season. In three starts last year against Detroit, Silva allowed 19 earned runs in 9 2-3 innings and had an 17.69 ERA.

Silva gave up four runs and six hits, but needed 94 pitches to finish five innings, and the damage could have been worse if not for a few diving and spinning defensive gems by Beltre at third base.

Seattle pulled even 1-all in the bottom of the third on Ronny Cedeno's solo homer — the only mistake Porcello made — only to see the tie disappear in the top of the fourth.

Miguel Cabrera walked on a 3-2 pitch after a long at-bat, then quickly found his way to third on a hit-and-run single by Carlos Guillen on the first pitch.

Inge didn't wait either, doubling past a diving Beltre on Silva's first offering to score Cabrera. Guillen came home moments later when Silva threw wildly in the dirt and behind left-handed batter Josh Anderson to the backstop.

Detroit added one more when Inge made a sprawling slide around catcher Jamie Burke's tag to score on Santiago's squeeze bunt.

Notes: Seattle 1B Russell Branyan got the day off with a sore back he suffered after a hard slide into home plate in Friday night's victory. Manager Don Wakamatsu expects Branyan will be available Tuesday against Tampa Bay. ... Detroit had 12 hits Sunday and has at least eight hits in all 12 games this season. ... SS Betancourt committed consecutive errors in the eighth, his first two errors of the season. He had 21 last year.