David won the game between two Goliaths.

Danny Zardon, a pinch hitter who lost his starting job earlier this season, hit a walk-off single down the third base line, and top-ranked LSU beat No. 2 Texas A&M 4-3 on Thursday night at an electric Alex Box Stadium.

Jared Foster scored on Zardon’s ninth-inning dinger that just stayed in fair territory, hopping past third base as about 8,000 sent the Box – really – rocking for the first time this season.

Starting pitcher Jared Poché pitched seven innings of six-hit ball, LSU got two bases-loaded strikeouts from a pair of relievers and the Tigers surged into the Southeastern Conference lead in the series opener of what’s thought to be the first No. 1-versus-No. 2 showdown in the history of Alex Box Stadium – old or new.

“As soon as I hit it, I was just hoping it was fair,” said Zardon, who has not started a game since March 19 and didn’t make the travel squad to Georgia last week. “It was real close to being foul. Thank God it was (fair).”

LSU recovered from a 2-0 deficit after the first inning, and the Tigers, leading 3-2 entering the ninth, overcame a blown save from closer Jesse Stallings to win a 13th game in the last 14.

Zardon saved the day. He chopped reliever Andrew Vinson’s 2-1 breaking ball over third base. Third base umpire Joseph Smith made his emphatic fair call, and Foster, who reached via a single and stole second, rounded third and easily scored.

LSU players flooded out of the dugout and raced toward Zardon, almost in disbelief standing at second base. Zardon started the season as LSU’s starting third basemen before being demoted to the bench after committing a host of errors.

The guy didn’t make the 27-man travel squad just a week ago.

The only reason he was in this game? Coach Paul Mainieri wanted the righty to face A&M lefty reliever Ty Schlottmann in the seventh inning. He replaced Chris Sciambra in the lineup.

“You’ve got to give a lot of credit to Danny,” Mainieri said. “He didn’t make the trip last week. He practiced all week with a great attitude, and I told him earlier in the week that he was going to get an opportunity and to be ready.”

Zardon won a wild one for the Tigers (36-6, 13-5 SEC) against the Aggies (36-6, 12-6) in this heavyweight battle between the top two teams in the nation. The pair entered tied for the lead in the SEC and had played five one-run games in the last six meetings.

Make it six.

LSU needed bases-loaded strikeouts from Parker Bugg and Collin Strall (3-0) in the eighth and ninth innings after Stallings blew his third save in the last six weeks. Stallings allowed a leadoff triple and tying single in the ninth before Jake Godfrey and Strall saved the Tigers.

Strall got his bases-loaded strikeout on a full count to send the Box into a fury.

The Tigers broke a 2-2 tie in the seventh when Schlottmann misfired Mark Laird’s lightly hit chopper to second base. Jake Fraley, who began the inning by walking, stormed home for the that go-ahead run.

LSU got a gem from Poché, who struck out one, walked none and allowed just two base runners in his final five frames in a raucous environment at the Box.

This one had the feel of a super regional from the start – as to be expected.

All 10,000-plus seats at Alex Box are sold out for the three games, and each will or has aired on regional or national television. In fact, Thursday’s game – originally set for ESPNU – was promoted to ESPN2. Friday’s game was moved from digital-only to SEC Network’s alternate channel, and Saturday’s series finale will air on the network’s primary channel of ESPN.

More than 100 fans formed a line at the Alex Box ticket office more than two hours ahead of first pitch.

“I told (A&M) Rob (Childress) after the game,” Mainieri said, “‘I think we’re going to have games like this for the next 10 years, so we might as well get used to it.’”

On Thursday night, No. 2 jumped on No. 1 early.

A&M dinged up Poché, rolling up four hits and two runs on the sophomore through the first two frames. LSU’s come back began in the fourth with some nifty base running.

Hale walked and moved to second on a timely hit-and-run from Kade Scivicque. Scivicuque’s shot, a light chopper, was able to get through the right side because the hit-and-run took A&M second baseman Ryne Birk out of position.

Andrew Stevenson used his speed to beat out a double play in the next at-bat, scoring Hale from third, and Chris Chinea followed with an RBI single through the left side to tie the game.

A&M starter Grayson Long, a junior who entered with a 2.73 ERA, didn’t look the same after that frame in a starting duel against Poché.

He retired 10 of the first 12 LSU batters before that fourth inning. LSU had seven base runners against him in the fourth, fifth and sixth innings. He led off the seventh by walking Fraley, and Foster then bunted him to second before the Aggies yanked Long.

Zardon, batting .417 against lefties, replaced Sciambra as Schlottmann’s first batter. He walked before Laird’s soft chopper to Schlottmann. The pitcher turned to second and misfired low, allowing Fraley to score the go-ahead run.

Bugg stood tall in the eighth under intense pressure in a 3-2 game. He allowed a one-out single before Foster made his second error at second base. Bugg walked Hunter Melton before getting the inning-ending K, a rousing strikeout.

Bugg pumped his fist twice, and LSU player leaped from the dugout to celebrate with him. Zardon had them storming out an inning later.

“You don’t really get a much better feeling out of baseball,” Poche said. “That’s about the highest you can get. A lot of people play this game for moments like that. Danny just came through in the clutch and did it for the team.”

Follow Ross Dellenger on Twitter: @DellengerAdv.