HOUSTON • The Cardinals have played themselves into such a bind on this road out of contention that a genuine gem like J.A. Happ pitched Monday gets lost in the blur of potholes and wrecks already littering this trip.

Happ, Houston's replacement ace, pitched well enough in his two-hit shutout to cool the hottest of teams. He settled for blanking the Cardinals. The lefty made swift work of the reeling Redbirds, throwing the Astros to a 3-0 victory at Minute Maid Park in a breezy two-hour game.

Cardinals manager Tony La Russa called it an "outstanding exhibition of pitching."

Not that his club can afford to appreciate it.

The Cardinals lost for the sixth time in seven games, and they assured themselves a losing record on this 10-game tour of losing teams. Coupled with Cincinnati's extra-inning win Monday, the Cardinals slipped to six games behind the first-place Reds in the National League Central. Instead of an opportunity to chomp into Cincinnati's lead, this trip - featuring series against three teams that had a combined .404 winning percentage before Monday's games - has become a deflating trudge. The Cardinals can't shrug off an evening like Happ's as the inevitable good pitcher having a great night at their expense.

Games are too few, the deficit too large and victories too precious.

"We need to string wins together," La Russa said. "That's what we're trying to do, and we haven't been successful on this road trip. The only thing we have in our favor is there are games left. When our heart is beating, we're going to keep playing. We're capable of putting something together.

"Let's see if we can do it."

For the fifth time in his six starts with the Cardinals, Jake Westbrook delivered a quality start. Westbrook (1-3) allowed three runs on nine hits through his seven innings. Houston's first run scored on a bloop double that took a fortuitous bounce into foul territory. The Astros' final run scored on a double play. Sandwiched in between was Westbrook's biggest mistake - a ball hit off the left-field wall by rookie Brett Wallace for an RBI double in the seventh inning.

Wallace was the Cardinals' top prospect until traded to Oakland in last summer's Matt Holliday deal. Back from a two-game break necessitated by a five-for-45 slide, Wallace set a career high with three base hits, all off Westbrook.

"It's definitely fun to play them tough," Wallace said. "We're trying to grow as a team with our young guys and stuff. ... They're in the playoff race right now."

This trip has offered evidence to the contrary.

Westbrook's start Monday was the first quality start of the trip for the Cardinals. Their starters arrived in Houston with a 5.67 ERA on the trip. The offense has been ragged, throwing up 10 runs in a loss one day and managing four or fewer in four of the past six games. For contrast, Houston returned to Minute Maid after a 6-4 trip that included a 2.53 ERA from its starting rotation and a four-game sweep of the defending NL champion Phillies.

Wallace, acquired in a subsequent deal, and Happ were both spoils of Houston's deal that sent ace Roy Oswalt to join those Phillies. Happ was the major-league bounty received from Philly as an immediate proxy for Oswalt in the rotation.

Happ (5-2) has pitched the part.

The lefty, unbeaten at Minute Maid, allowed one runner to reach scoring position Monday. Colby Rasmus only got there after his walk and a sacrifice bunt from Westbrook. Happ got ahead of more than half of the batters he faced and finished his third career shutout with a perfect ninth.

"He hit all the different edges, and he did it with several different pitches, and he did it from the first inning to the last," La Russa said. "He never really gave us much to hit. The couple times he did, we hit it hard."

And those were outs, too.

Two of the hardest hit balls of the evening resulted in three outs for the Cardinals. In the fourth inning, Matt Holliday clubbed Happ's offering to one of the deepest nooks of asymmetric Minute Maid. Near the point where the hill in center field slopes down to the warning track in deep center, Michael Bourn tracked Holliday's launch some 430 feet away from home plate.

"At that part of the park, you've got to get all of it," Holliday said. "I hit it good, but I didn't get all of it."

In the eighth, Yadier Molina provided the Cardinals' second base hit of the game, and Colby Rasmus followed with a laser - right at Wallace. The first baseman snared the line drive and tapped first base for the unassisted double play.

Westbrook deserved such luck.

In the first inning, Carlos Lee skied a fly ball that landed inches inside the foul line in shallow right field, in a triangle of Cardinals fielders. The ball then kicked into foul territory far enough to allow Hunter Pence to score from first base.

Westbrook's games have been complicated by erratic defense or, more recently, a complete absence of offense. He's lost twice on this trip and received a sum total of two runs of support.

Westbrook pointed to Wallace's RBI double and Wallace scoring on the double play ball in the seventh as the runs that undermined his outing.

"If I keep it to one run there, it makes it a little easier for us because every hitter is a possible tie ballgame from there," the righty said. "Happ pitched a great ballgame. Chalk it up to that. Move on. We can't win multiple games in one night. ... (But) this team we have, we should be capable of putting together wins."