CHAMPAIGN, Ill. -- Illinois needed about seven weeks to go from relative non-entity to top 10 team at the season's beginning.
It needed a month after that to slide out of the rankings and put an almost certain NCAA Tournament trip into some real peril.
And Thursday night, it required only 0.9 seconds to breathe serious life into its at-large hopes.
Tyler Griffey's uncontested layup as time expired lifted the Fighting Illini to a 74-72 upset of No. 1 Indiana, marking the fifth consecutive week the nation's top-ranked team lost.
Griffey broke wide open after a mix-up by the Hoosier defense -- Cody Zeller collided with a teammate and no one picked Griffey up -- and took an inbounds pass by Brandon Paul. Griffey's shot beat the horn by about two-tenths of a second.
The play survived a video review by the officiating crew, which had to fight its way through the students that stormed the floor as the shot went through the net.
"I fought through Zeller and Christian Watford, I think, and made a curl cut," Griffey said. "I was wide open. The only question was whether I would dunk it or lay it in."
Griffey finished the night with 14 points for Illinois (16-8 overall, 3-7 Big Ten), which snapped a three-game losing streak overall and a four-game skid at home. Griffey, who had a team-high eight rebounds, also ended a string of 20 straight misses from the 3-point line when he sank one early in the second half.
But his heroics wouldn't have been possible without clutch work from Paul and D.J. Richardson, as well as surprisingly stout defense in the final 3:36 with the Hoosiers (20-3, 8-2) leading 70-61.
Richardson, who scored a game-high 23 points, ripped off eight in a row to forge a 70-70 tie with 1:17 left. After Victor Oladipo converted a twisting layup with 50.3 seconds on the clock to give Indiana a two-point lead, Paul sank two free throws with 37.2 ticks left for a 72-all deadlock.
Paul was nervous on his first foul shot, banking it home.
"I just had to calm down on the second one," he said.
Richardson then stole the ball from Oladipo with five seconds left, but Oladipo rejected his layup, sending it out of bounds. That set up Paul's pass from the short corner to an unguarded Griffey.
Hoosiers coach Tom Crean was asked if he considered using any of his two timeouts before his team's last possession or the Illini's inbounds play.
"Absolutely not," he said. "I'd do it the same way again. I didn't want to give them a chance to set up a lob play at the rim. We just didn't communicate at the end."
Zeller paced Indiana with 14 points and sixth man Will Sheehey hit for 13, 10 in the first half. Christian Watford added 12 points but also made six turnovers and Jordan Hulls scored 11.
The teams slogged through the game's first 12 minutes, struggling offensively for reasons not completely related to their opponents' defense.
Indiana handled the ball as though it were coated with soap, committing six turnovers, while Illinois settled for long jumpers and made 7 of 21. But the Hoosiers finally quit making mistakes and started filling the basket.
They scored on 11 of their final 12 possessions of the first half, with Sheehey supplying eight points in a 25-14 outburst over the half's final 7:42. When Zeller swished two free throws with 1.8 seconds remaining in the half, Indiana took a 41-29 lead to the locker room.
The Hoosiers upped their advantage to 62-49 with 9:57 left on Jeremy Hollowell's 3-pointer and still led by 10 with 4:21 remaining. But they only scored on one of their final five possessions.
"Great win for our program," summed up Illini coach John Groce. "But it's just one win and we have to be ready Sunday at Minnesota. We have to do the same things there we did tonight."
NOTES: Indiana and Illinois have combined for eight wins this year over Top 25 teams, with each owning a nation-best four. Butler, Cincinnati, Duke, Louisville, Michigan and Syracuse are tied with three. ... This was just the second game against a No. 1 team in nine years for Illinois. After a 91-73 rout of then-No. 1 Wake Forest on Dec. 1, 2004, the Illini didn't play another top-ranked squad until Jan. 22, 2011, falling 73-68 to Ohio State. ... Indiana entered the game having made 118 more free throws than its opponents shot (447-329). It was 13-of-14 in this one, while Illinois sank 13-of-15.