Josh Harrison went 2-for-5 to take the lead in the NL batting race, but Jay tripled and scored the winning run in the seventh long after his hustling first-inning catch had aborted a potentially big inning for the Bucs.
"At the end of the day, that play by Jay in the first inning might have won the game," Pirates manager Clint Hurdle had to concede, even after three hours of spills, chills, ups and downs in a typical game in a typical NL Central race.
Labor Day, of course, represents the conclusion of the summer's last big Holliday Weekend.
That is not a typo. Matt Holliday's seventh-inning single scored Jay with the decisive run, and his earlier two-run double into the opposite-field gap had begun the Cardinals' comeback and earned Gerrit Cole's admiration.
"He's probably the strongest human in world," marveled Cole. "You jam him, and he hits it to the warning track in right-center."
The loss dropped the Bucs three games out of the National League Central lead behind the Cardinals, who are alone in first place for the first time this season following the Brewers' simultaneous loss to the Cubs.
The division standings are as tight as possible. So are the games being waged by the Pirates, who are two games out of a Wild Card spot. "Waged" is correct, because "playing" doesn't connote as much tension.
This was the Bucs' fourth consecutive one-run game, bringing their season total atop such tightropes to 53.
Andrew McCutchen, for one, thinks they'd better start handling the heights a bit better.
"It's another game we should have won," said McCutchen, whose 454-foot solo homer in the seventh had been the Bucs' final salvo. "There's certain situations in the game that good teams have got to key on, and it's something we've got to do. We've gotta keep battling, and not let these games slip out of our hands, because it's September and we gotta get going."
There would have been more breathing room Monday if not for Jay. The Bucs already led, 2-0, on Neil Walker's two-run double off 14-game winner Lance Lynn, when Starling Marte blistered a pitch to dead center with two men on base and running with two outs. Playing at medium depth, Jay had to race the ball to the wall -- and won, with an above-head catch.
"Without question," St. Louis manager Mike Matheny said when asked whether he considered that a game-changer. "They were putting some good swings right from the top. You could tell they were feeling good, and Lance was fighting to find a real nice feel for the good pitches in the bottom of the zone. They were making him pay."
Harrison had begun the opening rally with a single, and after doubling in the fourth owned an average of .313, two points higher than league runner-up Justin Morneau. Harrison finished 2-for-5 and at .311 is tied with Morneau.
"I'm not really worried about it," Harrison said. "Still a lot of games left. Gotta keep grinding."
Holliday sparked the Cards to their second impressive comeback in as many days. They had overcome a 5-0 deficit to the Cubs on Sunday. In its last three games, St. Louis has scored 27 runs; Holliday has driven in 12 of them.
"That's what he does, why he hits in the middle of the lineup," Hurdle said. "He puts himself in good position to drive in runs with good at-bats."
Or, as Cole saw it, "You have to execute. You have to be on your game when you face these guys."
Asked to carry a load becoming familiar to the Pittsburgh rotation -- an early, but frozen, lead -- Cole was about to cross the seventh-inning finish line with it when Kolten Wong tripped him up with a pinch-hit, game-tying two-run homer with one out in the seventh.
Cole went ahead of Wong to an 0-2 count on 95- and 96-mph fastballs. Then he wasted an 88-mile slider, and came back with another 96-mph cutter Wong deposited in the home bullpen for the Cardinals' first pinch-homer of the year.
Speed-wise, it was the same 1-2 pitch that two batters earlier had caught Daniel Descalso looking at strike three. Location-wise, this 1-2 pitch was inferior.
"Yeah," Cole said, "I executed that pitch [to Descalso], but I didn't get it in there [to Wong]. Threw it right in his wheelhouse."
The tone had been established. Jay followed with an opposite-field liner that, instead of curving into the boxes in the left-field corner, rattled around two bars of the railing before bouncing away from Marte for a triple. Soon thereafter, Holliday pulled his game-winner off reliever John Axford.
After the Pirates had made it 3-0 on Andrew Lambo's RBI double in the second, Lynn barred home plate, an unsettling reminder of Pittsburgh's last two games. Jumping into a quick lead has not been a problem for the Bucs. Adding on some runs has.
A 3-0 first-inning lead on Saturday survived for a 3-2 win over the Reds, but a 2-0 second-inning lead on Sunday over Cincinnati became a 3-2 loss.
As soon as Lynn departed, having surrendered eight hits and those three runs in six innings, McCutchen rousted the Pirates from that late-game funk. He turned Kevin Siegrist's 3-1 pitch into a leadoff homer in the seventh, setting the lead at 4-2.
McCutchen's 21st home run was no cheapie. At an estimated 454 feet into the third deck, it was the second-longest by a visiting player in the nine seasons of Busch Stadium III (Arizona's Paul Goldschmidt hit one two feet farther).