St. John's trailed for much of the final 10 minutes of regulation but tied the game at 58 on a Simon layup with four seconds left in the second half.
Simon finished with 24 points, Bashir Ahmed added 22 and Clark had 20 to lead the Red Storm (15-15, 4-13 Big East) to just their fourth conference win.
Paul Jorgensen had 17 points off the bench and Kelan Martin had 17 to lead the Bulldogs, who had their two-game winning streak snapped.
Relying almost solely on their starting lineup, the Red Storm held the Bulldogs to 35 percent shooting, but St. John's attempted 19 fewer field goals, connecting at 47 percent.
Led by their talented bench, including Jorgensen and Nate Fowler, who added 10 points, the Bulldogs' reserves outscored the Red Storm's, 32-0.
Fowler had a clutch 3-pointer with just over a minute left to give Butler a five-point lead, but he turned the ball over with 10 seconds left, and St. John's tied it.
Ahmed had 11 points and Simon added nine in the first half as St. John's built a 28-25 halftime lead. The Red Storm shot 44 percent in the first half while holding Butler to 36 percent shooting, including 27 percent from 3-point range. The Bulldogs hurt their chances by shooting 29 percent from the free-throw line in the first half, finishing at 50 percent for the game.
Tariq Owens added nine points, eight rebounds and three blocks for the Red Storm.
St. John's concludes its regular season on Saturday with a noon showdown at Providence. Butler ends its season on Saturday night at 8 p.m. against Seton Hall.
--Field Level Media
Butler | St. John's | |
Paul Jorgensen 17 | Scoring | Justin Simon 24 |
Aaron Thompson 5 | Assists | Justin Simon 5 |
Sean McDermott 7 | Rebounds | Justin Simon 10 |
Kamar Baldwin 3 | Free Throws Made | Justin Simon 6 |
Sean McDermott 4 | Steals | Justin Simon 4 |
Nate Fowler 1 | Blocks | Tariq Owens 3 |
Team | Points | FG% | 3PM-3PA | FTM-FTA | Assists | Rebounds | Blocks | Steals | Turnovers |
Butler | 68 | 35.1 | 10-35 | 6-12 | 14 | 35 | 2 | 13 | 17 |
St. John's | 75 | 47.3 | 4-12 | 19-23 | 8 | 37 | 8 | 10 | 24 |