CHAMPAIGN, Ill. -- John Hart had played 33 minutes of basketball for Purdue this season before Tuesday night's game against Illinois.
Hart wasn't even listed in the game's official score book, costing the Boilermakers (No. 15 ESPN/USA Today, No. 13 AP) a technical foul and two points at the free-throw line when he did play. The Illini said they knew nothing about him.
Hart more than made up for the technical and introduced himself to Illinois with 14 points, five of them in an early second-half run that gave the Boilermakers a lead they rode to an 84-78 victory.
"Our guy obviously made a mistake and he wasn't in the score book," Purdue coach Matt Painter said. "It cost us two points. It's a pretty good trade out."
JaJuan Johnson led Purdue with 24 points.
The win ended a three-game losing streak for Purdue (15-3, 3-3) and kept the Boilermakers in the thick of a crowded Big Ten, in a fifth-place tie with Ohio State and Minnesota.
The loss dropped Illinois (12-7) to 4-2 in the conference and two games behind Big Ten leaders Michigan State.
Demetri McCamey led the Illini with a game-high 28 points, including 13 from the free-throw line. But he missed six free throws, and the Illini were 17-of-29 (58.6 percent) from the line.
"Demetri played a heck of a ballgame," Illinois coach Bruce Weber said. "It's just the free throws."
After trailing 32-28 at the half, Purdue opened the second half with a 15-4 run.
Hart keyed the run, first with a fast break layup that tied the score at 32 and then with a 3-pointer that gave the Boilermakers a 35-32 lead.
"We had no energy to start the second half," Weber said. "It's baffling."
The game started to slip away from the Illini even before halftime, though.
Purdue went cold from the field midway through the first half, failing to find the basket from the field for 7:01. But Illinois didn't do much with the opportunity.
The Illini led 16-12 at the start of that stretch, with 10:52 on the clock, and 26-20 when Moore broke the ice at 3:51.
In between Robbie Hummel and Johnson kept Purdue going with two free throws each.
But Illinois could only blame itself. The Illini were 4-for-12 from the field over those seven minutes, including 0-for-3 from 3-point range.
Purdue then closed the gap to 28-26 on a jump shot by Hart with 53 seconds left in the half.
Only an unusual technical -- called when the officials noticed after Hart's first points that he didn't appear on the official roster -- let Illinois widen its cushion. McCamey hit both free throws for a 30-26 lead and Illinois led 32-28 at the half.
"I thought they outplayed us more than a four-point difference, especially on the glass," Painter said of the first half.
Illinois held a slim 23-21 rebounding edge at half time but had 11 offensive boards -- and only four second-chance points to show for them.
Weber complained about his team's missed opportunity.
"We actually played pretty good on the defensive end but not on the offensive end," he said. "We could have grabbed the game but didn't."
Purdue was effective at the free-throw line, hitting 27-for-34 (79.4 percent).
And the Boilermakers, after hitting just 10 of the 30 first-half shots, finished 27-for-56 (48.2 percent). They hit 65.4 percent -- 17-for-26 -- of their second-half shot.
Illinois held Purdue's leading scorer, Hummel, to 11 points, but McCamey said the Illini failed to make the changes it needed to when Painter put Hart in the game.
"The game is all about adjustments, and we didn't adjust tonight," he said.
Painter credited Hart, who played 18 minutes Tuesday, with the spark he said Purdue has lacked.
"I thought John had an edge to him, just from not playing," Painter said.
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Maryland point guard Melo Trimble, considered a lock to leave the program before struggling in the second half last season, has withdrawn from the NBA draft and will return for his junior season.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.