The fourth-seeded Red Storm, who have won a BIG EAST-leading five tournament titles, will play for the championship for the first time since 1999. Louisville was eliminated from the tournament with its second loss of the week.
St. John's had 14 hits against four Louisville pitchers with Baltz and Paul Karmas getting three hits each. The Red Storm held the Cardinals to just seven hits and two extra-base hits on the day.
St. John's got on the board in the bottom of the first when Greg Hopkins reached on a fielder's choice allowing Scott Ferrara to score from third. Baltz staked the Red Storm to a 2-0 lead in the third inning on a base hit to right which scored Matt Wessinger.
Louisville got one back in the top of the fifth, making it 2-1 on Drew Haynes' sacrifice fly, but the Red Storm increased their lead in the bottom half of the inning on Wessinger's RBI single to center and Baltz's base hit down the leftfield line, making it 4-2.
The Cardinals again made it a one-run game on Andrew Clark's RBI single in the top of the seventh inning. But Kevin Kilpatrick got a double play to get out of the inning, allowing St. John's to take a 4-3 lead into the home half.
Louisville got the tying run in scoring position on Phil Wunderlich's leadoff base hit to center and a wild pitch. But the Red Storm bullpen came up big again as Ryan Cole worked out of the spot with a strikeout and a grounder to second.
St. John's made it 5-3 on Scott Ferrara's base hit to left, which scored Sean O'Hare. Closer Daniel Burawa allowed two baserunners in the bottom of the ninth, but got J.J. Ethel on a line drive to first to end the game.
Stephen Rivera (4-2) got the win in relief for St. John's after working two innings, while Burawa picked up his 10th save of the season and his second of the tournament. Bob Revesz took the loss for Louisville, falling to 1-1.
The game was delayed by rain for 130 minutes after the top of the seventh inning. Louisville leftfielder Drew Haynes and head coach Dan McDonnell were ejected in the top of the sixth.