Astros rookie homers on first pitch in majors

The last Houston player to homer in his first career at-bat was Charlton Jimerson on Sept. 4, 2006, at Philadelphia.

"He showed up about 6:30 and jumped in a uniform and had a pretty good start," Cooper said. "He really made it big. We were looking a little stale until he got that hit."

Arias (1-0) gave up two hits and struck out six in five impressive innings. It was his first major league start after 18 relief appearances with Colorado. He got the ball in place of Brandon Backe, scratched because of soreness in his arm during a bullpen session Saturday.

LaTroy Hawkins pitched a scoreless eighth. He has not allowed a run in 16 games since coming to the Astros in a trade with the New York Yankees on July 30.

Jose Valverde worked the ninth for his NL-leading 41st save in 47 attempts. He has recorded saves in a club-record 14 straight appearances.

Snell (6-11) went six innings, allowing three runs and six hits.

Phillies 8, Marlins 6

At Philadelphia, Jayson Werth hit a three-run homer and Jimmy Rollins had three hits and three steals. The Phillies closed within 1 1/2 games of first-place New York in the NL East.

Joe Blanton (2-0) pitched five shaky innings to earn his first win since Aug. 2, and Brad Lidge finished to remain perfect in 35 save chances. Lidge put the tying runs on base before escaping the jam by striking out Wes Helms and Jorge Cantu.

Padres 4, Dodgers 0

At San Diego, Adrian Gonzalez hit a two-run homer off former teammate Greg Maddux (7-12) and the last-place Padres snapped the NL West-leading Dodgers' eight-game winning streak.

Cha Seung Baek (5-9) combined with two relievers to four-hit the Dodgers, who have a 1 1/2-game lead over Arizona. Los Angeles leapfrogged the Diamondbacks into the division lead with a three-game weekend sweep at Dodger Stadium. Maddux dropped to 1-3 with the Dodgers.

Giants 6, Diamondbacks 2

At San Francisco, Tim Lincecum boosted his bid for the NL Cy Young Award, handing Arizona its fourth straight defeat.

Lincecum (16-3) struck out nine in 8 1-3 innings, the longest outing of his career, and lowered his NL-leading ERA to 2.54. Bengie Molina hit a three-run homer off Yusmeiro Petit (3-5).

Reds 5, Brewers 4

At Milwaukee, Jeff Keppinger's double capped a three-run rally in the ninth against Brewers closer Salomon Torres (6-5).

Milwaukee's wild-card lead was cut to three games over Philadelphia with 18 to play. The Brewers and Phillies play a four-game series beginning Thursday in Philadelphia.

Francisco Cordero earned his 28th save in 34 chances.