ST. LOUIS -- Greg Garcia is the latest sign that this appears to be a charmed season for the St. Louis Cardinals.

The rookie pinch-hitter picked the bottom of the eighth inning Friday night to launch his first major league homer, a solo shot that erased a 2-1 deficit and helped St. Louis notch a 3-2, 10-inning win over the Chicago Cubs at sold-out Busch Stadium.

The Cardinals (49-24) scored the winning run in equally preposterous fashion. Chicago right fielder Mike Baxter, brought in to play on the infield's right side when the Cubs opted for a five-man infield with the bases loaded and no outs in the 10th, committed a throwing error as he tried to erase pinch-hitter Peter Bourjos at the plate on a bouncer by shortstop Jhonny Peralta.

But none of that happens without Garcia, who didn't homer in 61 games and 250 at-bats this year at Triple-A Memphis before earning a call up to the majors June 19.

"I'm just trying to get on base," he said. "I'm not a power hitter by any means. I hit a fastball and put a good swing on it, and I was fortunate that it got out of here. I haven't played here long enough to know what is and isn't a homer here."

A .283 hitter in more than 2,000 minor league at-bats, Garcia walloped just 27 long balls, hitting no more than 10 in a season. But he connected with a 3-1 fastball from reliever Pedro Strop, driving it 408 feet into the first row in center field as the sellout crowd of 45,558 erupted.

Firing his fist in the air between first and second, Garcia sprinted around the bases and later took a curtain call at the urging of manager Mike Matheny.

"His reaction was the best," Matheny said of Garcia. "I knew he'd put together a good at-bat, but I didn't expect the ball to be leaving over the center field wall. It's a special day."

There have been a lot of special days and nights for St. Louis, which improved to 27-7 at home and maintained an eight-game lead in the National League Central over Pittsburgh with its fourth straight win.

Meanwhile, Chicago (39-33) absorbed its third straight loss and dropped 9 1/2 games behind the Cardinals, wasting a strong outing from starter Jake Arrieta. After allowing an RBI triple to left fielder Randal Grichuk in the second, Arrieta retired 17 of the last 19 men he faced.

Arrieta gave up just three hits and a run in seven innings, walking two and fanning seven, and departed with a 2-1 lead, courtesy of a sacrifice fly by third baseman Kris Bryant in the seventh.

"I got into a groove and was able to hold them off most of the night," Arrieta said. "But they did what they do. They fought back and got us. This was a tough one. We were right there."

The Cubs outhit St. Louis 12-6 and had starter John Lackey in trouble for most of the game, but couldn't produce a hit with a runner in scoring position except for Baxter's game-tying RBI single in the fourth.

Lackey scattered eight hits in seven innings, yielding two runs with three walks and five strikeouts. Four Cardinal relievers teamed up for three scoreless innings, with Seth Maness (2-0) picking up the win by fanning pinch-hitter Jonathan Herrera to strand two men in the 10th.

Bourjos touched reliever Justin Grimm (1-2) for a leadoff double to start the winning rally. Second baseman Kolten Wong followed with an infield hit which caromed off second base and third baseman Matt Carpenter drew an intentional walk to set the stage for St. Louis's sixth walk-off win.

However, Garcia, the grandson of former big league manager Dave Garcia, a native of nearby East St. Louis, Illinois, was the unexpected star in the Cardinals' latest victory.

"It's indescribable," Garcia said. "You can't recreate that feeling anywhere else in this world."

NOTES: St. Louis LHP Jaime Garcia (groin cramp) is in line to make his next start Tuesday night against the Chicago White Sox, according to general manager John Mozeliak. Garcia left Wednesday night's 6-1 win in Miami in the eighth inning after limping home following a base hit. ... Chicago 3B Kris Bryant (flu-like symptoms) was back in the lineup Friday night after leaving Thursday's game with the Los Angeles Dodgers before the third inning. ... Cardinals LF Matt Holliday (quad) will try running next week to gauge his progress. If he can run without pain, Holliday, who has been out since June 9, could go on a rehab assignment.