SEATTLE -- Seth Smith powered Seattle past Houston and put the Mariners closer in the wild card chase.He hit a pair of home runs and drove in four runs on Sunday to help the Mariners beat the Houston Astros 7-3. His effort backed up a strong performance by lefty Ariel Miranda as the Mariners remained in the thick of the congested wild-card race.The Mariners (79-70) are one game behind Toronto, which holds the second wild-card spot.Smith had a solo shot in the third and a three-run shot in the fourth, both on 3-1 pitches from Doug Fister (12-12). Smith had been 0-for-10 in his career against Fister but the eight-year veteran had a plan.Guys know what theyre doing when they are pitching and able to pitch to the corners, Smith said. You try to take the close ones, try to get into a good hitters count when they come after you.Smith, who now has 16 home runs on the season -- one short of his career high -- was patient enough to work both into hitters counts then connected on fastballs into the right-field seats.Youre constantly learning, how to approach at-bats, knowing what kind of swing you have going into a game, knowing what the pitcher is trying to do to you, Smith said. Over the course of a career you kind of fit the pieces a little better together.Fister said, I was just trying to attack with my sinker; he put a couple good swings on balls -- clearly.I just didnt execute today, thats what it comes down to. Balls down, balls up, all over the place. I let my team down.Miranda (5-1), acquired in a trade with Baltimore on July 31 for lefty Wade Miley, went seven innings -- his longest outing in 10 starts with Seattle -- allowing two runs on three hits. He walked one and struck out eight.Heck of an outing, Mariners manager Scott Servais said. Hes on a heck of a roll. We certainly needed it. Hes gained so much confidence. You can certainly can see it.Miranda has won all four of his starts in September. The Cuban defector said, through an interpreter, its been a dream of mine (to be in a playoff chase) but never been there. Its really great to get there. Im happy with the work Ive been doing and happy to help the team.Houston manager A.J. Hinch said Miranda has a good fastball and a good split-