D'Angelo Harrison made up for a quiet night by hitting a late go-ahead 3-pointer and coming up with a big block in the final seconds, as St. John's knocked off No. 20 Notre Dame, 67-63, at Madison Square Garden.
Harrison had just eight points -- 12 below his season average -- but none were bigger than his triple that put St. John's in front, 64-63, with 2 1/2 minutes remaining.
Blocks by Harrison and Chris Obekpa in the final minute, as well as Jamal Branch hitting two free throws with 7.1 ticks to go, sealed the outcome and stopped the Red Storm's two-game skid.
JaKarr Sampson netted 17 points, Phil Greene IV had 13 and Amir Garrett added 11 for St. John's (10-7, 2-3 Big East), which held the Fighting Irish to 1- of-9 shooting from 3-point range.
Notre Dame (14-3, 2-2) came in hitting 42 percent from long range, but found little success offensively outside Eric Atkins, who led all scorers with 21 points to go with four assists and six steals.
Jerian Grant logged 14 points and committed six of the Irish's 12 turnovers, while Jack Cooley was limited to 10 points and watched the final 9:36 from the bench.
"They really guarded the heck out of us with their speed and over the course of time, it wore on us," Notre Dame head coach Mike Brey said of the Red Storm defense.
Notre Dame, which had its 12-game winning streak snapped by Connecticut last Saturday, fell behind by 12 midway through the second half before "storming" back and taking a two-point lead down the stretch.
A Grant layup gave the visitors a 63-61 edge before Harrison drained an NBA- range 3-pointer, which wound up being the last field goal made by either side.
Notre Dame's final four possessions saw Grant throw the ball out of bounds, Harrison come from behind to block Tom Knight, Pat Connaughton getting denied at the rim by Obekpa and Grant missing a 3-pointer at the buzzer.
Sampson made 1-of-2 free throws prior to Obekpa swatting away a shot by Connaughton, who had the ball go off his head and out of play. The sequence gave St. John's the ball back with a two-point lead and 7.6 seconds left, and Branch's clutch makes at the stripe gave the hosts the victory.
"I'm just proud and really pleased with our kids," St. John's head coach Steve Lavin said. "We're just a young team that's a work in progress."
Harrison was held without a field goal in the first half, though Sampson's 14 points helped the Red Storm take a 32-31 lead into the break.
Cooley scored inside for a 39-37 advantage early in the second half, but the Red Storm answered with the next 10 points. A pair of Greene jumpers bookended the run, which was highlighted by Garrett's dunk off Harrison's no-look pass.
Harrison's first field goal was a 3-pointer from the corner that pushed the margin to 55-43 with under 11 minutes to play. The 12-point difference lasted less than six minutes, as Notre Dame rattled off 18 of the next 22 points.
Atkins led a balanced attack during the flurry with two assists and five points, including a layup in transition for a 61-59 advantage with 4 1/2 minutes remaining.
Harrison scored in single-digits for the second straight game after logging 21.5 points over the first 15 ... St. John's made just 3-of-17 shots from behind the arc ... The last Irish win over the Red Storm at MSG was on March 5, 2004 ... Notre Dame's Scott Martin pulled down a game-high eight rebounds but did not register a point.