"We need to win the game [Sunday]," manager Clint Hurdle said. "The volume of games [remaining] are shrinking each and every day. The guys know the urgency.
"Tonight we just got beat by a really good pitcher."
Oswalt (14-9) was more than good Saturday night -- he was phenomenal. The right-hander lit up the strike zone with a mid-90s mph fastball, a devastating sinker, a nasty slider and a curveball that seemed to be traveling in slow motion.
"He's one of the best pitchers in the league," Chris Iannetta said. "This is what you expect out of him almost every time out."
Brad Hawpe fisted a ground ball up the middle in the fifth for the Rockies' only hit of the game. Oswalt breezed through Colorado's lineup with ease, striking out six and throwing 70 of his 102 pitches for strikes.
He looked just as fresh in the ninth as he did in the first, hurling 95-mph fastballs that left Hawpe and Atkins in the dust to end the game.
"That was electric stuff, no doubt about it," Hurdle said.
Jeff Francis (4-9) pitched well for the second straight outing, a positive sign that the shoulder troubles that plagued him earlier this season have completely subsided. He only gave up one hit through four innings and escaped a jam in the fifth by retiring three straight batters with runners on the corners.
He wasn't as fortunate in the sixth. Miguel Tejada hit a one-out single to left, and Hunter Pence golfed a 3-1 changeup into the left-field stands to put the Astros ahead for good.
That was the only mistake Francis made in 6 1/3 innings. The left-hander surrendered seven hits, struck out five and walked two.
"It was another step up for him coming off of his last outing," Hurdle said. "He made good pitches and kept us in the game."
It was a solid start, especially considering the Astros came into the game hitting .282 against lefties, but Francis needed an Oscar-worthy performance to trump Oswald on this night.
"The game can be cruel," Francis said. "Oswalt pitched his butt off tonight. It was the Roy Oswalt Show, that's for sure."
While Oswalt was electric, perhaps the biggest spark came on a massive home-plate collision in the eighth.
With two on and two out, Oswalt hit a sharp single to right. Reggie Abercrombie tried to score from second, but Hawpe threw a laser that one-hopped to home. Iannetta fielded the ball and slightly turned to his left before being plowed to the ground by Abercrombie.
Iannetta bounced right up and showed the umpire the ball as the crowd cheered like they were at a UFC fight.
"I got a quick glimpse of him before he hit me, and I tried to spin off to deflect some of the contact," Iannetta said. "I was just trying to hang on."