The fans stormed the court and Frank Sinatra's "New York, New York" blared over the sound system.
The Aztecs raced to a huge lead at noisy Cox Arena, blew it all, then rallied to beat Mills and the Saint Mary's Gaels 70-66 on Wednesday night to reach the semifinals of the NIT.
"It's an understatement for me to say that this was an important victory for our program," said Fisher, who arrived at SDSU in 1999 and revived its sad-sack program.
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Billy White scored 17 for the Aztecs (26-9), who will play Baylor (23-14) in the semifinals on Tuesday night at Madison Square Garden.
Fisher was part of two NIT championships while at Michigan, as an assistant to Bill Frieder in 1984 and as head coach in 1997. Fisher coached Michigan to the NCAA title in 1989.
SDSU and Saint Mary's (28-7) both felt they should have been in the NCAA tournament. As it is, the Aztecs are the last Mountain West Conference team still playing in the postseason.
This is the deepest SDSU has advanced in a national postseason tournament in its Division I history.
SDSU blew a 13-point second-half lead, but Saint Mary's never took the lead. Tim Shelton posted up for the go-ahead basket with 48.6 seconds left and Richie Williams made three free throws in the final 26 seconds as the Aztecs held off the Gaels.
The fast, normally exciting Mills had a miserable end to his season. He was on the bench at the final buzzer, having fouled out with 10.8 seconds to go. He scored a game-high 18 points but had a horrible night shooting, going 7-for-24 overall and 4-for-13 on 3-pointers.
"It was one of those days," said Mills, the Australian Olympic star who is widely expected to turn pro following his sophomore season.
Mills -- who came in shooting 86.7 percent from the free-throw line -- missed the front end of a one-and-one with 34.9 seconds left and the Gaels trailing 66-64. SDSU's Kyle Spain rebounded and Mills fouled Williams, who made both ends of a one-and-one for a four-point lead.
Mills made a layup with 14.9 seconds left and Williams answered by making the second of two free throws to make it 69-66. After a timeout, the Gaels inbounded the ball to Mills but he inexplicably lost the ball out of bounds.
Mills drew his fifth foul and Williams again made the second of two free throws for a 70-66 lead.
The Aztecs were just 4-of-8 from the line in the final 1:42.
SDSU had lost to Saint Mary's in consecutive appearances in the John Wooden Classic, including 67-64 on Dec. 13.
SDSU jumped to leads of 13-0 and 18-3 as Mills and the Gaels started cold. Saint Mary's pulled within five late in the first half before SDSU took a 39-28 halftime lead.
"We were letter perfect," Fisher said of the opening salvo. "We were making every shot. We were turning them over. They were on their heels.
"We jumped off to a phenomenal start," Fisher added. "We owe our crowd. In the 10 years I've been here, I have not heard a louder crowd for the duration."
The game drew a sellout crowd of 12,414 to Cox Arena, including former SDSU and NFL football star Marshall Faulk, who sat courtside, next to San Diego Chargers coach Norv Turner.
"I didn't think we were quite ready for the storm that hit us to start that game," Saint Mary's coach Randy Bennett said. "They are not used to not winning. As a coach, you can't ask for anymore than to have a chance to win that game down the stretch."
The Aztecs were up 46-33 early in the second half before Saint Mary's started closing the gap. Saint Mary's tied it at 64 on Mills' fast-break layup with 2:02 left but could never take the lead.
"We had every excuse in the world to lay down and die," Mills said. "But we are a tough team."