ST. LOUIS -- Good thing for the Houston Astros that they didn't load the bases with one out in the seventh inning Tuesday night.

Manager A.J. Hinch was prepared to lift starter Doug Fister for a pinch-hitter. But when Marwin Gonzalez was nipped at first on a close play, moving Colby Rasmus and Carlos Gomez into scoring position, Hinch let Fister hit.

Fister rewarded his manager's gamble with a two-out, two-run single up the middle, putting the wraps on Houston's 5-2 win over the St. Louis Cardinals at Busch Stadium.

Fister, who had two career RBI prior to his first-pitch knock off reliever Seung Hwan Oh, sacrificed and bunted into an out in his first two plate appearances of the night.

"I really take it serious," Fister said of his infrequent at-bats. "Whether it's getting down bunts or swinging the bat, you've got to be able to help yourself and at least put the ball in play. You're one of nine when you're playing in a National League park."

In his real job, Fister (7-3) won his sixth straight decision, shackling an offense that entered the game batting .269 and averaging 5.6 runs per game. He required only 87 pitches to work 7 1/3 innings, yielding just five hits and two runs while walking one and fanning six.

Knowing that Fister was attacking the strike zone, St. Louis became more aggressive to no avail as the night progressed, making eight outs on first and second pitches.

"It all starts and almost ends with him," Houston manager A.J. Hinch said of Fister. "He had an incredible game in almost all aspects. He changed his game plan a little bit to pitch into a couple of areas of the strike zone where he normally doesn't pitch, but all in all, that was a wonderful effort."

Only two swings did any kind of damage to Fister. Matt Adams led off the second with a homer to center, just over the leaping Gomez, and Brandon Moss ended a string of 14 straight men retired when he cracked a two-out homer to left in the sixth.

That blast, Moss' 15th in only 163 at-bats, cut the Astros' lead to a run. But any momentum the Cardinals derived from it ended in shocking fashion an inning later.

Rasmus, a former Cardinal who homered to start the fifth and snap a 1-1 tie, singled with one out to knock out starter Jaime Garcia. Gomez reached on an error by Adams at first on Oh's first pitch, and Gonzalez's infield out set up an unlikely clutch hit.

The odds that Fister would stroke a two-run single off any pitcher were pretty long. The odds that he would do it off Oh, who has permitted just 18 hits over 34 1/3 innings, bordered on astronomical. After all, Fister hadn't collected a hit since last August, when he was working for the Washington Nationals, and American League pitchers entered the night with just one RBI all year.

St. Louis manager Mike Matheny certainly didn't expect Fister to hit, or succeed.

"Yeah, yeah," Matheny said when asked if he was surprised at the result. "Good move -- because it worked."

Garcia (4-6) permitted eight hits and four runs, three earned, over 6 1/3 innings with no walks and two strikeouts. The Cardinals (35-31) saw a season-high five-game winning streak conclude and fell to 15-17 at home this year.

Will Harris pitched a clean ninth to earn his fourth save for Houston (31-35), which upped its record on its nine-game road trip to 3-5.

Hinch only had to look at his starting pitcher for the reason why the Astros bumped fists at the end of a speedy 2-hour, 18-minute game.

"He pitches quick, he pitches efficiently, he throws strikes and we have to be ready," Hinch said of Fister. "Hitters don't wait around to attack him. It seems like we have a little more energy and attention to detail with him on the mound."

NOTES: Houston selected INF Danny Worth from Triple-A Fresno and started him at third base, batting him second. The 30-year old Worth was batting .340 with eight homers and 36 RBI. ... St. Louis C Brayan Pena (left knee) halted his rehab assignment at Double-A Springfield temporarily to deal with a personal matter. Pena is 3-for-19 in six games, dating back to June 7. ... Astros RHP Luke Gregerson was placed on the family medical emergency list, and the team also designated minor league RHP Juan Minaya for assignment.