Auburn led early in the game, but Illinois took the lead for good, appropriately considering how the game played out, with four minutes left in the first half at 41-39 on a pair of free throws.
For the game the Illini shot 40 free throws while Auburn was 10-16 at the foul line.
The Tigers dropped to 5-7 for the season with their second consecutive loss while Illinois improved to 13-1.
Senior guard Frankie Sullivan led the Tigers with 21 points while senior center Rob Chubb added 13 points and five rebounds. Sullivan was 8-17 from the field and 5-12 on threes. As a team the Tigers made 11-23 treys.
Rob Chubb launches a hook shot for the Tigers.
Junior forward Allen Payne had his best game of the season with 10 points and a team-leading 10 rebounds.
"We came in here to get the job done and we didn't," Auburn coach Tony Barbee said. "We gave ourselves some opportunities."
Barbee noted that the Tigers shot the ball well enough and rebounded well enough to win on the road, but said his players didn't come up with enough of the 50-50 balls late in the game to pull off the upset. "At the end of the day it comes down to those mean, nasty plays that I talk about," the coach said. "We had a lot of those opportunities to come up with today."
Barbee also didn't like the excessive number of ball-handling errors. "We had 20 turnovers against a team that did not press--not one time," he said. "We had 11 from our veteran guards. It is just unexcuseable--just careless with the ball."
Illinois had nine fewer turnovers, allowing the Illini to overcome a 39-31 Auburn advantage in rebounds.
Auburn hit 29-60 field goals (48.3 percent) while Illinois was 25-52 (48.1 percent) while making 4-15 three-pointers.
The Tigers played without freshman guard Jordan Price, who was not available for the game with his foot and ankle in a protective boot due to a stress fracture in his ankle.
Both teams shot the ball very well in the first half. The Tigers made 16-30 field goals and 5-10 threes while Illinois was also 16-30 from the field. Illinois led 47-42 at the break by making seven more free throws than the Tigers in the opening 20 minutes.
Illinois built the lead into double figures at 57-46 with 13:48 to play on a basketball by senior forward Sam McLaurin, but Auburn steadily cut into the lead and narrowed the gap to 68-67 with 4:29 left on a three by Sullivan.
However, Illinois went on a 9-1 run to build up enough cushion to survive a late push by the Tigers who scored six points in the last 14 seconds on treys by Sullivan and Wallace.
"The disappointing thing is we played well enough to win this game," Barbee said. "The couple of things that made the difference in winning that we didn't do had nothing to do do with sticking it in the hole. We didn't care of the basketball at a high level and we didn't win the battle of the 50-50 balls that made a difference down the stretch.
"If we can clean up that area we have got enough to go on a real run," Barbee said. "What I told them it is not me, it is you guys. You have got to understand and embrace that change that we have got to make."
The Tigers return to action for their final pre-conference game with a 6 p.m. CST tipoff at home vs. Florida State on Wednesday.