ST. LOUIS -- In the fourth inning Friday night, with runners on first and second with one out, Lance Lynn gloved Hunter Pence's grounder, wheeled toward second base and threw away the Cardinals' dream of winning their 19th National League pennant at home.

Before the inning mercifully ended, the Giants scored four unearned runs and dispatched the Cards to the airport for an unwanted to flight to San Francisco and Sunday night's Game 6 of this NL Championship Series.

It's a game the Cardinals didn't want to play. But this is a team that does nothing easily. It's best at coming off the mat.

NLCS

And maybe Lynn wishes he'd taken a sure out at first base rather than try for a double play with a throw that cost the Cards a chance to celebrate on a cold night at Busch Stadium.

St. Louis still needs just one win to meet the Tigers in the World Series, a repeat of 2006, when the Cardinals won the championship in five games.

AT&T Park will be treacherous regardless, but the haunting reality that San Francisco spotted powerful Cincinnati two victories in the best-of-five NL Division Series and stormed back with three consecutive wins to advance to the NLCS hovers like a storm cloud.

"We never thought for a second that [the Giants] are going to go away," said subdued St. Louis manager Mike Matheny. "They're a good team, and they're going to keep fighting, we know that. It just comes down to execution. They executed today better than we did."

With Barry Zito pitching the most important game of his long career, Lynn's errant throw was all the Giants needed to break through.

Lynn had allowed just one walk over the first three innings, but he gave up two quick singles to start the fourth. After Lynn struck out the dangerous Buster Posey, he had a chance to escape with an inning-ending double play.

Pence ripped a comebacker to the mound, but Lynn's throw to second base bounced off the front of the bag into center field as Marco Scutaro easily scored from second.

Brandon Belt popped out for the second out, but after Gregor Blanco walked to load the bases, Brandon Crawford drove home two runs with a single to center.

Then, with what might have been the biggest insult of the game, Zito bunted perfectly down the third-base line and beat out the throw to first base as the fourth run crossed the plate.

Matheny said Lynn was pitching "as good as we've seen him all season those first three innings. And the fourth -- a couple of quick base hits, a strikeout and the ball back to him."

Matheny agreed Lynn could have gone to first base for a sure out "and you're sitting with two outs, runners on second and third. And [then] gets a popup on the next guy [Belt]."

Instead, Lynn made the bad throw to second, opening the floodgates.

The 25-year-old right-hander, who led the Cardinals with 18 wins during the regular season, was unable to get out of the fourth inning in Game 2 last Saturday against the Giants even though he no-hit them through the first three innings.

Yet Lynn wouldn't compare Friday night to that loss.

"I turned around and threw a ball into center field," he said. "I could have gotten myself out of the inning. It's definitely my fault."

For Lynn, taking the sure out at first base wasn't an option.

"I'm going to try to get two and get out of the inning there," he said. "It's 100 percent you're looking for two there, all the way."

"I don't mind him being aggressive if he's got the play," Matheny added. "He just made a low throw. And to do it over again, I'm sure he'd like to take the easy out at first base and then try his luck on Belt.

"It just didn't work that way, and we were stuck in a spot where it just kind of spiraled at that point in a hurry. And that was the game."

Zito, in earning the fifth postseason victory of his career, completely shut down the Cards' offense.

This has been a major concern this postseason, except for Thursday night's 8-3 victory which gave the Cardinals a 3-1 lead in the best-of-seven series and set the stage for what they hoped would have been the clincher on Friday.

Although St. Louis has two chances to win one game, it must improve its run production, or the Giants, who faced elimination in three games against the Reds, could pull off another miraculous comeback.

The Cardinals should be somewhat comfortable knowing that since 1985, when the NLCS moved to a seven-game format, 14 teams have held a 3-1 advantage and only two have failed to make it to the World Series.

St. Louis' hitting, however, must improve.

The Cards were 0-for-7 with runners in scoring position Friday night and left seven runners on base. They are just 4-for-24 in this series with runners in scoring position.

Matheny summed up the predicament the Cardinals are in: "[The Giants are] excited about going home, and rightfully so. We've got our hands full. So, hopefully, we'll catch a flight tomorrow and have everybody get their heads right and show up Sunday for a tough game."

And minimize the errant throws.