SAN FRANCISCO -- Given the San Francisco Giants' recent issues with their bullpen, the St. Louis Cardinals were confident they could make something happen in the most important inning of their season Saturday night.

And they were right.

Kolten Wong's sacrifice fly capped a two-run rally in the ninth inning as the Cardinals overtook the Giants for a critical 3-2 victory.

Trailing 2-1 and two outs away from a potentially disastrous third consecutive loss in the series, the Cardinals now go for a split when a pair of rookie right-handers, St. Louis' Alex Reyes and San Francisco's Albert Suarez, square off Sunday afternoon.

"I can feel it, and I know the guys can feel it," Cardinals manager Mike Matheny said of the playoff race. "We know where everybody stands. But you really do have to put (previous losses) behind you. We've done a good job of that."

The loss dropped the Giants (79-69) five games behind the Los Angeles Dodgers (84-64) in the National League West and into a tie with the New York Mets (79-69) for first place in the NL wild-card race.

The Cardinals (77-71), who were staring at falling four back with 14 to play, are within two of the Giants and Mets.

The Cardinals trailed by a run when Jedd Gyorko singled off the fifth Giants pitcher, Sergio Romo, with one out in the ninth.

Giants manager Bruce Bochy went to struggling Santiago Casilla, and after pinch-runner Tommy Pham stole second, Yadier Molina drew a walk.

Randal Grichuk singled past the outstretched glove of Giants shortstop Brandon Crawford to tie the score, sending pinch-runner Jose Martinez to third.

"We huddled up and said if we got Molina (up) there, he's had success off Romo, Casilla would be a better matchup," Bochy explained of the change. "That's what the plan was; it didn't work out. (If) that groundball was a little to the left, we wouldn't be talking about it."

Left-hander Matt Reynolds replaced Casilla, but Wong greeted him with a liner deep enough into center field to allow Martinez to tag and score easily with the decisive run.

Seung Hwan Oh, who took over in the eighth inning, allowed two-out singles to Eduardo Nunez and Denard Span in the ninth before getting pinch-hitter Conor Gillaspie to pop up to end the game.

"I didn't plan on using him for two innings," Matheny said of Oh. "But he was so good (in the eighth), it's good to have that as an option."

Oh (5-3) got the win. Castilla (2-5) took the loss as well as picking up his ninth blown save of the season.

The Giants have blown 28 saves this season, matching a franchise record.

"We played well," Bochy insisted, shaking his head. "It's (Casilla's) tough luck there on that groundball. Once (Grichuk) hit it, I thought it was a double play. It just got through."

In a matchup of a guy the Giants acquired to help in their 2015 playoff push and the $90 million replacement for 2016, the Cardinals' Mike Leake and San Francisco's Jeff Samardzija pitched well enough to win.

In fact, Samardzija appeared headed for his first win in September with 6 2/3 innings of five-hit ball, limiting to the Cardinals to one run, a product of Brandon Moss' home run three batters into the game.

Samardzija walked four and struck out four.

Will Smith, Javier Lopez and Derek Law combined to retire four consecutive batters, allowing the Giants to take a 2-1 lead into the ninth, before the next three relievers couldn't close the deal.

"It stinks," Samardzija assured of the outcome. "Sometimes it doesn't go your way. But you can't let it affect you (the next day)."

Leake pitched six innings, allowing two runs on seven hits. He walked one and struck out three.

"We knew it had to start with the start," Matheny said of Leake's effort. "He gave us a chance."

Wong reached base in all three of his plate appearances before the game-winning sacrifice fly with a single and two walks for the Cardinals, who improved their best-in-baseball road record to 44-30.

Moss' homer was his 27th of the season.

Nunez, Span and Hunter Pence had two hits apiece for the Giants, who fell to 2-4 on their seven-game homestand.

The Giants outhit the Cardinals 9-7.

For the second time in three nights, the Giants took a lead in the middle of the game on a sacrifice fly by a pitcher.

This time it was Samardzija in the fifth inning, after singles by Nunez and Span put runners at the corners with no out out.

Samardzija gave the Giants a 2-1 lead with his flyball to right field, but a relay throw from Stephen Piscotty nailed Span trying to advance, turning it into a double play.

The Giants erased the 1-0 deficit created by Moss' first-inning homer with a run of their own in the second. A single by Pence, extending his hitting streak to 11 games, and double by Brandon Belt produced the run.

NOTES: The win was the Cardinals' sixth in 66 games this season in which they trailed entering the ninth inning. ... The Giants' 28 blown saves matches the previous record set in 2004 and tied in 2005. ... RHP Santiago Casilla's nine blown saves are the most by a Giant in one season since Robb Nen had nine in 1999. ... The Cardinals held a 10-minute team meeting before taking the field for pregame warmups. ... Cardinals LF Matt Holliday (fractured thumb) waved off a scheduled live batting practice session for the second time in a week because of swelling in the thumb. His return is in doubt. ... Olympic gold medalist Aly Raisman threw out the game's ceremonial first pitch.