The Explorers had knocked off mighty Butler and a decade of mediocre basketball was forgotten in a flash.
Out of timeouts, Galloway sprinted the length of the court for the winning basket with 2.7 seconds left to send La Salle to a 54-53 victory over No. 9 Butler on Wednesday night.
Fans stormed the court in wild elation for the biggest win for La Salle (13-5, 3-2 Atlantic 10) in 33 years. There was some confusion after Galloway's basket and fans were ordered off the court. Butler had attempted a last-second heave that was way off the mark. Officials huddled with both coaches and they decided the final score stood. It was mayhem again as fans rushed the court for the second time in minutes.
Let them celebrate twice: La Salle hadn't defeated a top 10 team since 1980.
"It's the greatest feeling ever," Galloway said. "It's one of the greatest wins ever in my life. I know it is for my teammates, too."
Butler (16-3, 3-1) had lived on last-second victories this season, including a buzzer-beater Saturday against Gonzaga. Just not at La Salle.
Andrew Smith's layup with 8 seconds left put Butler ahead 53-52 and it appeared the Bulldogs would survive another thriller.
Not so fast. Galloway took the inbounds, drove past Smith and Roosevelt Jones and banked the shot for the stunner that helped flood the court with delirious fans. La Salle last defeated a Top 25 team on March 3, 2001 against No. 18 Saint Joseph's, 91-90. The last time La Salle defeated an top 10 team was on Jan. 30, 1980, against No. 8 Notre Dame, 62-60, according to STATS LLC.
La Salle's Sam Mills hit a jumper with 32 seconds left to make it 52-51. But Mills missed the front end of a 1-and-1 to give Butler the ball with 10.9 seconds left. Smith gave Butler the short-lived lead. Galloway hit the basket to remember.
"You could tell how everybody celebrated how happy they was," guard Tyreek Duren said.
Galloway, battling some family issues, broke down in tears in the postgame press conference as he talked about his family.
Duren had 16 points and six assists and Mills scored 11 for the Explorers. La Salle shot 52 percent (13 of 25) from the field in the second half.
Butler's leading scorer Rotnei Clarke missed his third straight game with a severely sprained neck. No decision has yet been made about Saturday's home game against Temple.
Clarke was hurt when he crashed head-first into a padded basket support at Dayton on Jan. 12.
But Clarke's absence hadn't slowed the surging Bulldogs until Wednesday. Butler had won 13 straight including Saturday's buzzer-beater over then-No. 8 Gonzaga, 64-63. The streak has moved the Bulldogs into the top 10 for the first time since Feb. 18, 2008.
They won't be ranked there much longer. Smith scored 16 points, Kellen Dunham hit three 3-pointers and scored 15 points and Jones had 14.
"I've got to do a reasonable job of keeping this in perspective," Butler coach Brad Stevens said. "We basically won at Dayton without Rotnei. We beat Richmond and Gonzaga without Rotnei, and we lost a one point game at La Salle against a very good team without Rotnei. I think we have to keep that in perspective and move on."
This was the second time in two nights students rushed the court in Philadelphia. On Tuesday, Villanova fans stormed the Wells Fargo Center after a 73-64 win over No. 5 Louisville. This one meant a bit more at La Salle.
"It was a dramatic win for our players, our fans, our students. It was awesome," coach John Giannini said. "But am I going to tell you I'm shocked that we won? Absolutely not."
La Salle goes for two upsets in two games when it plays Saturday at No. 19. Virginia Commonwealth.
La Salle trailed by 10 points in the first half but never let the game get too far out of control.
Duren hit a 3 to make it 38-35 and Mills made two from the free throw line to cut Butler's lead to one. Duren drove the lane for the 41-40 lead and suddenly 3,400 fans sounded like 34,000. Garland followed with a 3 that gave La Salle a four-point lead and put the upset only 7:40 away.
La Salle was once like Butler back when Tom Gola, a three-time All-America, led the program to consecutive trips to the NCAA championship game in 1954 and 1955. The Explorers won the 1954 national championship.
But the team wouldn't remain among the elite and lean times hit the program for most of the last two decades. La Salle hasn't played in the NCAA tournament since 1992 and last season's NIT berth was its first since 1991.
For most of Wednesday night, the underwhelming decades didn't matter. Gola Arena, pretty much a high school gym plopped on a city campus, was packed with 3,400 fans full of school spirit and thirsting for an upset. Yes, the Explorers were a 2½-point betting favorite, but the oddsmakers were the only ones who considered the Bulldogs an underdog.
Butler could not shake La Salle in the first half. Galloway dunked off a turnover to keep it a three-point deficit, and Garland and Duren buried consecutive 3-pointers to cut Butler's lead to 28-23. Butler's 52 percent shooting to La Salle's 32 percent helped the Bulldogs lead 28-23 at halftime.