The Mets' John Franco (left) congratulates teammate Jay Payton after he hits a two-run HR in the ninth.(AP)

Because once you slice away the fat and drain away the grease, the skeleton of this series lies in the simple fact that the St. Louis lineup is stocked with five left-handed batters -- four when facing a lefty -- and the Mets' rotation begins with two very talented lefties: Hampton and Al Leiter.

The Cardinals were just 17-23 against left-handed starters this season.

They will face at least two, probably three and possibly four over the next several days depending on how long this series goes.

And they're not off to a very good start.

"I think, for us, one of the things I saw last year in the postseason is that we didn't match up starting pitching for starting pitching," said Mets general manager Steve Phillips, who traded for Hampton last December. "In these short series, the impact of your starting pitching is critical."

Remember the clutch at-bats of Fernando Vina, Jim Edmonds and Will Clark in the divisional series against Atlanta?

In Wednesday's opener, Cardinals lefties went 3-for-13 in seven innings against Hampton before relievers John Franco and Armando Benitez finished them off.

Worse, with runners on base, Cardinals lefties were 0-for-7.

Worse yet, with runners in scoring position, Cardinals lefties were 0-for-5.

"I didn't have the greatest stuff in the world tonight, but I was able to work to my strengths," said Hampton after winning the first postseason start of his career.

Said St. Louis manager Tony La Russa: "I thought that Hampton pitched an impressive game. In fact, I thought both he and Darryl (Kile) pitched impressive games. We had some chances with men in scoring position. He made quality pitches. So I mean, our guy gets the loss, but I thought they both were impressive, tough to hit.

"I just like the way we played. I didn't like the score. The ninth inning got away from us. But I saw a lot of good at-bats, and our defense was on its toes. I liked the starting pitcher. It's just that Hampton and the Mets were a little better."

It isn't only Hampton. Counting the last three games of their divisional series against San Francisco, the Mets' pitching staff has combined to toss 27 consecutive innings without yielding an earned run.

Momentum is such a fragile commodity in the postseason. The Cardinals romped over Atlanta so easily last week, everything went right. When they needed a key hit, they got it. When they needed a key pitch, they got it. When they needed a well-told joke, a five-course dinner or a new pair of spikes, someone was always there.

But somewhere between Wednesday morning and late Wednesday evening, someone rattled the Cardinals' cage.

Granted, everything is magnified in the post-season, and sometimes things do get blown out of proportion. Each inning, each at-bat, each pitch takes on added significance.

In this case, though, the warning signs are warranted. Unless the Cardinals unexpectedly discover a flock of right-handed hitters in their attic, things don't figure to get easier until at least Game 3.

And new math or old, St. Louis is in danger of falling into a 2-0 hole.

"(Game 2) is crucial only if you keep losing," Cardinals outfielder Eric Davis said. "It's not so bad if we go out and do what we have to do."

But the lefty-righty breakdowns in this series certainly favor the Mets.

"On paper," Phillips cautioned. "But Vina is a scrapper. And for a while, they outhit us tonight. The big thing is to keep out of the big inning. If they score, keep it to one run. Don't let them put a crooked number up."

Phillips certainly has acquired the pitchers to do it.

Hampton was 1-1 with a 2.20 ERA in two starts against the Cardinals during the regular season, while Leiter was 1-0 with a 1.29 ERA in one start.

And Vina, Clark, Edmonds and J.D. Drew certainly don't need to be reminded that left-handers mustered just a .118 batting average against Leiter this season.

"Obviously, there is a lot being said about them being left-handed dominant," Leiter said before the game. "And this year I have pitched the best I have ever pitched against lefties. I'm not quite sure why. But it is one of those things where once you start getting lefties out, you have more confidence and feel about what you are doing as far as setting them up.''

Oh, the Cardinals are set up, all right. It's just the nature of their lineup.

Now, we'll see whether the Mets can knock 'em down.

"We're a confident team right now, but we know it's far from over," Mets catcher Mike Piazza said. "It's a long series. We've been through a lot together. We've just got to keep the hammer down."