"You don't have that much time," he said.
Clemson (6-2), which defeated then-No. 12 Butler last Sunday, looked to have this one locked up, leading 51-28 early in the second half.
All the Illini did was pull off the biggest comeback in school history for a 76-74 victory Wednesday night in the ACC/Big Ten Challenge.
"All of a sudden, somebody told me we were down four. I was shocked," said a giddy Illinois coach Bruce Weber.
He had plenty of reasons to be happy. Illinois came into this one off losses to Utah and Bradley at the HoopTV Las Vegas Invitational. The chat rooms filled up with critics blistering the Illini for a lack of on-court leadership from a team with four upperclassmen in the starting lineup.
It was that experience that fanned the historic comeback.
Mike Davis led Illinois with 22 points. Center Mike Tisdale hit the go-ahead basket with 41 seconds left, then blocked David Potter's try to retake the lead on the Tigers' next trip down.
Point guard Demetri McCamey played under control in the second half despite having four fouls.
Freshmen Brandon Paul and D.J. Richardson combined for six 3-pointers to fuel the comeback.
Paul finished with 20 points in Illinois' biggest rally since beating Seton Hall 87-79 in 2000 after trailing by 21.
"It's a family, sticking together," Davis said. "We read all the articles, no leadership. We stepped up tonight."
The Illini (5-2) looked finished when Jerai Grant's dunk gave the Tigers the 23-point lead. That's when they went on 35-10 run to move in front.
"We said to ourselves, we can't get down," Tisdale said. "Coach wanted us to play hard. We didn't do that in the first half."
Demontez Stitt missed a driving shot at the buzzer for Clemson as Illinois broke a three-game losing streak in the ACC/Big Ten Challenge.
Stitt made two foul shots at the end in the Tigers' 70-69 win over Butler last weekend. He said he had a good look at the basket, but could not finish the layup.
"We can't let games like this slip away," he said. "You get up by 20, you can't relax."
Unfortunately for the Tigers, it's happened too often the past few seasons.
In 2007, Virginia closed with a 19-2 run to win 64-63. Then last February, Florida State went on a 23-4 second-half spurt to beat the Tigers 65-61.
Purnell said Clemson abandoned the defensive mindset that helped it build the first-half lead.
"We just kind of got away from who we have to be," he said.
Stitt led the Tigers with 15 points. Leading scorer Trevor Booker had just three of his 12 points in the second half. He had 10 rebounds for his third double-double this season.
Illinois' rally took everyone at Littlejohn Coliseum by surprise. It began with Tisdale's two free throws and a jumper by Davis. Paul's second 3-pointer of the run brought the Illini within 16.
Davis and Richardson each added three-point plays as the lead dwindled to 61-57.
Even Booker helped Illinois' cause, tipping in McCamey's miss a possession later. When Paul picked off a pass by Potter for a layup, the Illini were up 63-61 with its bench and a handful of fans going crazy as Purnell called time out.
Tanner Smith's 3-pointer with 2:01 remaining put the Tigers up for the last time, 74-72.
Richardson added a foul shot before Tisdale's winning bucket.
With the Tigers up 23-19, McCamey picked up his third foul and went to the bench.
When 5-foot-9 Andre Young squeezed past Tisdale, Illinois' 7-1 center, for a layup, a loud noise that sounded like a coach's clipboard hitting the court came from the Illini bench. Weber was quickly called for a technical foul by official Bryan Kersey.
Weber was stunned.
"I didn't do anything. What did I do?" he shouted as Kersey moved to the other side of the court.
Moments later, Booker collected a loose ball and was yanked to the ground by Dominique Keller, who drew an intentional foul. Keller quickly helped Booker to his feet.
When Booker made his free throws, Clemson was ahead 39-25 on the way to a 47-27 halftime lead.