Ron Oester tripled to begin a two-run sixth inning and singled home a run during a two-run seventh last night in Cincinnati to enable the Reds to move within a half game of the National League West lead with a 5-2 victory over the first-place Houston Astros.

The teams are scheduled to play the second game of their two-game series tonight.

Mario Soto (11-9) surrendered just five hits, striking out three and walking two, before weakening in the ninth. Tom Hume finished and earned his 13th save. Vern Ruhle (4-6) suffered the loss.

With the score tied, 1-1, in the sixth, Oester opened with a triple to center. One out later, Dave Collins stroked an RBI single. Collins was forced at second on Ken Griffey's grounder but Dave Concepcion ripped an RBI double down the left field line.

Cesar Cedeno pulled Houston within 3-2 with a solo homer in the seventh, but Cincinnati added two runs in the bottom of the inning off Dave Smith. Joe Nolan walked, Ray Knight doubled and Nolan scored on an error by catcher Alan Ashby on the throw to the plate. Knight moved to third on the error and scored on a single by Oester.

Houston opened a 1-0 lead in the third on a homer by Craig Reynolds. The Reds tied the score in the fifth on a home run by George Foster, his 21st.