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LSU shortstop Josh Smith (4) looks at the ball after missing the catch, putting Florida State third baseman Drew Mendoza (22) safe at second in Game 1 of the NCAA Baseball Baton Rouge Super Regional between LSU and Florida State, Saturday, June 8, 2019, at LSU's Alex Box Stadium in Baton Rouge, La. Florida State defeated LSU 6-4.

Saul Garza missed second base.

The LSU catcher skidded to a stop after a hit to right field by Cade Beloso, just in time to watch Florida State touch the bag and muffle what could have been a breakaway inning.

It was the first time an LSU base runner had missed tagging a base all season, coach Paul Mainieri said — an untimely mistake in the fourth inning of Game 1 of the Baton Rouge super regional at Alex Box Stadium.

Florida State's 6-4 win Saturday was largely built on multiple mistakes the Tigers made.

LSU (40-25), now down 1-0 in the series, must beat Florida State (40-21) in consecutive games to reach the College World Series.

Game 2 starts at 5 p.m. Sunday.

"It's a fundamental of the game," Mainieri said of base running, adding that Garza has been playing through a foot injury he suffered a few weeks ago. "Somehow he misstepped and missed the base. We should have had (runners on) second and third with nobody out. Instead it's a runner on second with one out."

Two batters later, LSU's Chris Reid hit an RBI double, scoring Beloso. Had Garza still been on base, he would've scored as well.

LSU led 3-0 at the time — and later, in the fifth inning, the Tigers' aggressive base running restricted them to scoring just one run in what could have been another big rally.

Josh Smith and Zach Watson hit leadoff singles. Then Daniel Cabrera hit a one-out single up the middle.

Smith raced around third and crossed the plate.

Meanwhile, Watson rounded second, and he was tagged out in a rundown when Florida State cut off the throw home.

LSU did not score again.

Mainieri said Watson did exactly what he was supposed to do, even though the play resulted in an out.

"He did it perfect," Mainieri said. "There's going to be a play at the plate. He's taught to go and force the cutoff man ... (to) make a decision and concede the run or let the ball go through in an attempt to get the runner at home."

The play still took runs off the board — and all of a sudden, what could have been a cushy lead for reliever Todd Peterson turned into a bullpen crisis.

Peterson, whose 76 pitches Saturday were a season-high, left the seventh inning having retired a batter and given up a single.

He was relieved by Trent Vietmeier, who pitched two late innings in the regional-clinching win last Sunday over Southern Miss.

Vietmeier walked his first batter. It was the seventh of 10 walks for LSU — the team's most in a game since surrendering 11 walks in an 8-4 loss to Texas on March 2.

That brought up the heart of the Florida State batting order: three left-handed hitters, all with a batting average above .300 and a combined RBI total of 140.

LSU lost its only left-handed pitcher, freshman Easton McMurray, after he underwent season-ending shoulder surgery Feb. 21.

Mainieri said Friday that not having a left-handed pitcher to face left-handed batters this season has made games "a little bit more challenging," but he said he knew which LSU pitchers perform well against left-handed hitters.

Vietmeier entered Saturday's game with left-handed batters hitting .396 against him this season, which was the second-highest average among LSU pitchers.

"Somebody has to be in the game," Mainieri said Saturday. "Trent's got a nice little cutter and breaking ball, and I thought against the lefties there, he would have the best chance."

Vietmeier pitched his way into a full count with Florida State right fielder Reese Albert — and after Albert fouled off five pitches, he hit a three-run home run onto the roof of the Marucci Performance Center beyond right field to tie the game 4-4.

It was the second time in the postseason that the LSU bullpen surrendered a game-tying home run in the late innings. Southern Miss hit a game-tying grand slam off Zack Hess in the seventh inning of LSU's 8-4 win over the Golden Eagles last Saturday.

"Trent battled hard," Mainieri said. "(Albert) ended up winning the battle."

Devin Fontenot, who has held lefties to a .219 batting average this season, relieved Vietmeier to start the eighth inning.

Fontenot didn't last long, allowing a walk and a single during his third of the inning. Another walk by Hess set up a sacrifice fly for Florida State to take a 5-4 lead, which they extended to 6-4 in the ninth, when Albert homered to right again.

And in that ninth? 

LSU second baseman Brandt Broussard threw a double play opportunity into left field.

It was LSU's first recorded error of the game.

"This is the postseason," Smith said. "We've got to fix those things. Capitalize from their mistakes and not let our mistakes run us into the ground."