ST. LOUIS—If it’s possible to make up for six largely disappointing years in one game, Barry Zito did so Friday night.

With his team one loss from elimination, Zito stepped up and shut out the St. Louis Cardinals for 7 2/3 innings, leading the San Francisco Giants to a 5-0 victory that cut their deficit in the National League Championship Series to three games to two. The 34-year-old veteran of 13 seasons called it the greatest start of his career.

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“All things considered, this was probably the biggest,” Zito said.

You would, too, if your professional life had endured as many lows as Zito’s since he signed what is considered one of the worst free-agent contracts a team ever has given a player, $126 million for seven years. Six years into the deal, Zito has had one winning season—he went 15-8 this year—and never finished with an ERA below 4.03.

“He’s had his problems but he sure rose to the occasion,” said Peter Magowan, the Giants’ owner when Zito signed his mega-deal. “We should all be elated. He’s kept us in the season. We have a shot at the World Series because of what he did tonight.”

When the Giants made their run to the 2010 World Series championship, Zito wasn’t on the 25-man roster for any of the three rounds. But he didn’t complain and he never gave up.

“The guy showed up every day ready to go,” pitching coach Dave Righetti said. “He pitched his heart out in simulated games and tried to get himself ready for each step of the playoffs and World Series. He did it like a professional.”

“It was certainly a huge blow personally,” Zito said. “But you can’t pout and such. I worked on a lot of things that offseason and came back stronger for it.”

Perhaps as impressive as the manner in which Zito has dealt with his struggles was how he handled the Cardinals. St. Louis is known for pounding soft-tossing left-handers, and there’s not a softer-tossing lefty in the game. Zito’s fastball averaged 84 mph this season, the second-slowest in the majors after R.A. Dickey, and Dickey’s a knuckleballer.

But only once did Zito allow the Cardinals more than one baserunner in an inning, when he loaded the bases with one out in the second. He escaped when, after intentionally walking eight-hole hitter Peter Kozma, he got Cardinals starter Lance Lynn to ground into a double play.

Zito then retired 16 of the next 19 Cardinals before departing in the eighth when manager Bruce Bochy didn’t let him face Matt Holliday for a third time, even though Zito had struck out the Cardinals slugger twice.

Zito did not allow another walk and ended up striking out six, finishing several with a high fastball that topped out at 85 mph. When hitters are expecting off-speed, a well-placed heater can be as effective as one 10 mph faster.

“I know it’s not fast,” Righetti said. “But he has a way of getting people to pop it up or miss it. Even in his worst days, he’s always gotten a few strikeouts and it’s always been on a high heater and a curveball.”

If his work on the mound wasn’t impressive enough, Zito also showed off with the bat. A career .097 hitter, Zito contributed the final RBI in a four-run fourth that proved the difference in the game.

With a runner on third and two out, Zito noticed a well-placed bunt could score a run. So on the first pitch, he sent one down the third-base line and easily beat David Freese’s throw to first. Not known for his speed, Zito said it was the first bunt hit of his career.

Even TV star Matthew Morrison, who sang the national anthem, was impressed. Outside the visitors’ clubhouse following the game, he embraced Zito and said: "An RBI? What?"

“Surprised a lot of people there, including us,” Bochy said.

The Giants didn’t admit they were surprised to see such a stellar start from Zito, who had struggled in his previous outing in the Division Series and was passed over until Game 5 of the NLCS. But they all said they couldn’t be happier for him.

Zito’s wife of less than a year, former Miss Missouri Amber Seyer, was in the stands along with some of her family members. “He’s handled some pretty low stuff and the high stuff about the same,” Righetti said. “But inside, sharing it with his new wife and new family, he should feel great.”

“He’s such a good guy,” Magowan added. “He deserves good things to happen. And they did tonight.”

— Game 5 details: Recap | Box score | Play-by-play | Photos