ST. LOUIS -- Well before he took his only swing of the night that mattered, Chris Young was getting himself prepared for that opportunity.

Sitting on the bench Wednesday, he saw the Boston Red Sox going through relievers and reserve players as the game against the St. Louis Cardinals stretched into extra innings. He could sense that his turn was getting close.

Finally, in the 13th inning, he came off the bench and delivered an RBI single that gave the Red Sox a 5-4 victory, completing a comeback from an early 4-0 deficit.

"It was just one of those games that you stay loose and you're ready for a pinch hit, you're ready for a double switch," Young said. "You just never know what can happen. You try and stay ready. I think I was swinging the whole game because it was situations where I could have potentially come up."

Young was the next-to-last position player available to manager John Farrell.

"He's always ready," Farrell said. "He's always into the game. He's always thinking the game, talking the game in the dugout, understands situations. His spot came up big, and he found some outfield grass for the winner."

The winning rally started after reliever Sam Tuivailala retired the first two batters in the 13th. Mitch Moreland hit a ground-rule double, and the Cardinals intentionally walked Jackie Bradley Jr., bringing Young to the plate to hit for pitcher Fernando Abad (1-0).

"In that situation, you get a runner in scoring position and you're just trying to find a way to put the bat on the ball," Young said. "We battled and our bullpen did an amazing job to give us the opportunity to win the ballgame, and we're grateful for that."

Young hit the second pitch from Tuivailala for a single to left, scoring Moreland with the tiebreaking run.

"I felt like I made some good pitches, but the ball didn't fall in the right spot for us," Tuivailala said. "I felt the pitch to Moreland was the right pitch, it just fell. Against Young, I kind of left the curveball a little up, and he was able to get enough of the ball. It is what it is."

The Cardinals, who built a 4-0 lead in the first two innings against starter Rick Porcello, never could add on after that, opening the door for the Red Sox's comeback.

They had only seven hits over the final 11 innings, never getting a runner past second base.

"There were not a lot of opportunities," Cardinals manager Mike Matheny said. "We couldn't put hits on top of each other."

After being shut out for the first six innings, the Red Sox cut the lead to 4-2 in the seventh on a two-run homer from Bradley, his second in as many games.

Matheny thought the game turned in the eighth, when the Cardinals believed reliever Trevor Rosenthal had Dustin Pedroia struck out, which would have been the second out of the inning, but instead the pitch was called a ball by plate umpire Jeff Kellogg.

Xander Bogaerts followed with his second triple of the game to cut the lead to 4-3, and Bogaerts then scored on a sacrifice fly by Andrew Benintendi.

"That's a shame," Matheny said of the pitch to Pedroia. "That's strike three. That's a different game. I thought it was a shaky strike zone, and I thought it happened a number of times in big situations. We're never ones to make excuses, but it's a fact, a number of pitches got missed in big situations, and it ended up hurting pretty bad."

Abad, the seventh reliever used by the Red Sox, earned the win by allowing only one walk in two hitless innings. Ben Taylor pitched the bottom of the 13th, working around a two-out walk for his first career save.

"This one tonight was a lot of grit, a lot of character, a lot of competitive bats late in the game," Farrell said. "This was big for us particularly tonight. This is a big win. It's a huge shift. I think anytime you get this deep into an extra inning game when you're depleting your bullpen to come away with a win they feel like two at times."

Benintendi, despite getting the game-tying sacrifice fly in the eighth, was 0-for-5, extending his streak without a hit to 26 at-bats.

The Cardinals built their lead on a leadoff homer from Dexter Fowler in the first and a three-run second inning, getting four consecutive hits off Porcello before leaving the bases loaded.

Cardinals starter Mike Leake gave up two runs in seven innings, while Porcello allowed four runs in six innings.

NOTES: Red Sox 3B Pablo Sandoval will DH for Triple-A Pawtucket on Friday night as he attempts to work his way back from a sprained right knee that has kept him on the disabled list since April 25. ... RHP Hector Velazquez will be called up from Pawtucket to make his major league debut for the Red Sox on Thursday night in Oakland. A corresponding roster move has not been announced. ... The Cardinals had a pregame ceremony honoring the 50th anniversary of the 1967 team that defeated the Red Sox in the World Series. ... After a day off Thursday, the Cardinals will send RHP Michael Wacha to the mound Friday night against the San Francisco Giants. He did not start in the last turn through the rotation to give him extra rest and he will be making his first start since May 7.