ST. LOUIS -- In the Fox booth Friday night, Tim McCarver and Joe Buck kept talking about Barry Zito's fastball as if it were a Ford Focus leading the Indy 500. It topped out at 86 mph, reaching that peak just twice.

This is what it took to save the NLCS from becoming the dud that Detroit made of its series with the great capitulators of the Bronx. Zito's soft stylings jolted the whole affair, blocking the Cardinals from a hasty move into the World Series and putting them on a plane to San Francisco for a Game 6 Sunday.

They still have a 3-2 series lead over the Giants, and killing them off will require a stake to the heart, silver bullets and an explosive canister between their teeth inviting to Sheriff Brody to fire off a round as he shouts "Smile, you son of a …" Even then, the Cardinals might not go away.

But on Friday night, they were undone by a gentle soul who turned up at his news conference in a fedora that suggested he'd be sitting in on a jazz set as a follow-up act. Zito and his lukewarm heater dominated the Cardinals, 5-0.

If he had simply contained them for six innings, the Giants would have been thrilled. They signed Zito to a seven-year, $126 million contract in 2006, but their expectations for him dropped off as precipitously as his curveball on its best day.

After seven seasons in Oakland without a losing record, Zito moved across the Bay and lived below .500 for the next five. He received horrible run support, but still the transformation was too radical to explain.

People pointed to that soft fastball, to the radar guns registering 85 instead of 88, as they had during his Cy Young Award season of 2002. But Zito's fastball had dropped down to 85 mph by 2006, a year in which he went 16-10, beat Johan Santana in a playoff showdown and enticed the Giants to tender him what, at the time, was the most expensive contract ever for a pitcher.

The $126 million was excessive, even for a durable 28-year-old left-hander with a Cy Young in his past. It ended up having even equally excessive repercussions. The Giants developed an allergy to longer-term contracts. Zito's deal wasn't the only reason, but for an ownership group with an array of partners, it became the symbol of hazards in the baseball marketplace. Managing partner Peter Magowan had orchestrated the Zito deal, and when he stepped aside after the 2008 season, that $126 million contract was nudging him.

Above all, the contract affected Zito, who saw the deal as a demand to be more than he had been before. For any athlete, that would be damaging. For someone who had always been comfortably different, it was a disaster.

Zito needed to make peace with that 85 mph fastball, believing that it could work. But the complaints about velocity reached his ears and infiltrated even deeper. Never mind that the 88 mph of his early 20s said emphatically that he was not a fastball pitcher. If he could excel in that range, he could certainly achieve competence with a slightly discounted velocity. He already knew that, but for anyone trying to perform at a high level, the issue isn't what you know. It's how much you trust what you know. The critics' voices blurred what Zito remembered.

"I was looking at some old tapes from when I was in Oakland, and I was throwing 85-86 and getting guys out," Zito said a few weeks ago. "I pointed it out to my wife, because I was a little surprised."

He and Amber Seyer, a former Miss Missouri, married last winter. After Zito applied for the license, the San Francisco Chronicle contacted a county clerk, who said she had offered him a confidential version. "He said, 'Just give me a public one. I'm over myself,'" Joyce Whitney told the paper.

Zito had already proved that in 2010, when the Giants won the World Series without him, their most expensive player. Bruce Bochy remembered telling Zito that he had not made the postseason roster. "I think he went out and threw a bullpen [session] right away" the manager said.

He kept himself ready in case the team needed him. He cheered from the dugout. He never took a break from being a Giant. Even the most hostile fans started to come around, for reasons both sentimental and practical. In the end, Zito's contract did not stifle the franchise's efforts to build a contender. The club's aversion to long-term deals ebbed somewhat, and Matt Cain locked in at a price slightly steeper than Zito's.

Then came Game 5, against a team that devours left-handed pitchers. On a national stage, Zito took down the most tireless team in the majors, realigned some beliefs about velocity and success, and also unraveled a liability that became apparent as he switched leagues. His at-bats were comically awful in the beginning. Even on sacrifice bunts, he looked lost. On Friday, he knocked in one of the runs with the first bunt for a hit in his career. He put down the bunt, simply hoping to bring in a runner from third. That worked, and then he beat the throw to first with "my Arabian horse gallop."

When finished all the post-game interviews, Zito went to greet some friends in the corridor outside the Giants' clubhouse. They clapped and hollered as they saw him coming. "An RBI. What?" one of them bellowed, and everyone nearby laughed.

A bigger surprise, almost unfathomable before Friday, may be coming. If the Giants return home and win Games 6 and 7 behind Ryan Vogelsong and Cain, Zito will be the most reasonable choice to open the World Series. That's as unimaginable as the Cardinals' advancing from the wild-card round with the help of a poorly applied infield-fly rule. It's as incomprehensible as Tim Lincecum coming out of the Giants' bullpen, and as the Reds' losing their ace, Johnny Cueto, to an injury within minutes of starting the first round of playoffs.

The most shocking thinking of all, though, would be these two teams producing a dull series. That possibility has now come off the table, with the same arc as Zito's curve.