St. Louis ? A six-run inning was overkill for the Chicago Cubs, considering Mark Prior was on the mound.

Prior allowed three hits in eight sharp innings, and Randall Simon and Aramis Ramirez hit back-to-back home runs in the pivotal third as the Cubs defeated St. Louis, 7-4, Tuesday night.

“I’m not trying to go out and strike out 10 guys; I’m not trying to put up a shutout every time,” Prior said. “My job is to keep them from scoring as many runs as we do, and that’s the bottom line.”

The Cubs won for only the third time in 14 games at Busch Stadium the last two seasons, and moved a half-game ahead of the Cardinals for second in the tight NL Central and a half-game behind Houston. It was the first of eight games in 11 days between the rivals.

Garrett Stephenson (7-13) got knocked out early, perhaps opening the door for newly-acquired Sterling Hitchcock in the St. Louis rotation.

Hitchcock followed Stephenson, who allowed six runs on five hits in three innings, to the mound. The Cardinals have told Hitchcock he’d make a start soon. In his second appearance since being acquired Friday from the Yankees he allowed one run on three hits in five innings.

“I just like him pitching,” manager Tony La Russa said. “He’s done a good job out of the bullpen, and I’m sure he’d do a good job starting.”

Prior (13-5) has dominated in five starts since coming off the 15-day disabled list from a bruised shoulder Aug. 4. During that time he’s 5-0 with two complete games and an 0.69 ERA (three earned runs in 39 innings), lowering his overall ERA to 2.47.

He beat the Cardinals for the first time in three career decisions, striking out six and walking one. St. Louis had two baserunners in an inning only once, and Prior retired 14 of the last 15 batters he faced.

Chicago starter Mark Prior follows through on a pitch against St. Louis. Prior improved to 5-0 with a 0.69 ERA since returning from the disabled list following the Cubs' 7-4 victory Tuesday night in St. Louis.

Not every St. Louis player was impressed, however.

“His fastball is pretty straight,” said leadoff hitter Kerry Robinson, who was 0-for-4. “It’s not like he dominated anyone out there. I know he didn’t dominate me.”

Giants 3, Rockies 1

Denver — Jason Schmidt allowed four hits in 7 2/3 innings for San Francisco. The Giants have won six of seven since a season-long six-game losing streak and have won two of three without Barry Bonds.

Expos 14, Phillies 0

Montreal — Wil Cordero hit a pair of two-run doubles as Montreal rallied from an eight-run deficit.

Brewers 7, Reds 1

Cincinnati — Doug Davis (1-0) pitched a four-hitter, and Milwaukee won its eighth straight game. Geoff Jenkins had a career high-tying four hits, including a two-run homer, as the Brewers extended their longest winning streak since a nine-game string in 1997.

Pirates 4, Marlins 3

Pittsburgh — Jason Kendall hit a decisive two-run homer in the seventh inning for Pittsburgh.

Astros 18, Dodgers 4

Houston — Jeff Kent homered and drove in five runs, and Jeff Bagwell also homered for Houston. The Astros came within one run of matching the highest-scoring game in franchise history, last done in 1999.

Mets 6, Braves 5

Atlanta — Mike Piazza hit a three-run homer in his first game against Atlanta this year, and Timo Perez added a two-run double.

Padres 5, D’backs 4

Phoenix — Phil Nevin and Ryan Klesko hit consecutive RBI doubles in the eighth inning, and San Diego rallied from a four-run deficit to beat Arizona.