EVANSTON—Tre Demps scored 11 points and made three late 3-pointers to lead Northwestern to a 49-43 upset of in-state rival No. 23 Illinois on Sunday night.Drew Crawford added 14 points and JerShon Cobb had 11 for Northwestern (8-9, 1-3 Big Ten), which gave coach Chris Collins his first conference victory.Northwestern had lost four straight overall and three in a row in conference play, but snapped both streaks thanks to its defense. Following a one-point loss to DePaul on Dec. 27 to end nonconference play, the Wildcats lost by 27 against Wisconsin, 23 to Michigan, and 26 to Iowa before beating Illinois and holding them to 28.1 percent from the floor.Tracy Abrams had 13 and Rayvonte Rice had eight for the Fighting Illini (13-4, 2-2), who have lost two straight after four consecutive wins.Rice, who entered as the conference’s leading scorer at 18.8 points per game, didn’t get his first basket until there was 8:39 left in the second half. The redshirt junior guard was 2 of 11 from the floor and missed all five of his first-half shots. He had scored 19 points on 7-of-21 shooting in a 95-70 loss to No. 4 Wisconsin in Madison on Wednesday.After leading by as many as eight in the second half, Northwestern allowed Illinois to tie the game at 27 on Kendrick Nunn’s layup with 11:31 left. Demps, though, hit three 3-pointers in three minutes, the last giving Northwestern a 43-36 lead with 3:28 to go. Cobb’s layup with 1:53 left gave the Wildcats a 45-36 lead.Illinois thought it cut the lead to 45-42 with 55.9 left, but Joseph Bertrand was called for charging, wiping out his basket. The Illini got to within 45-43 when Rice hit a 3-pointer with 15 seconds left. Crawford hit two free throws with 14.3 seconds left, and Northwestern finished the upset.Northwestern held Illinois to a season low in points without junior guard Dave Sobolewski, who missed the game due to a concussion he sustained in practice.During Illinois’ loss to the Badgers — its most lopsided defeat of the season – the Fighting Illini shot just 31.6 percent from the floor and had just Rice and Bertrand score in double figures. That didn’t improve much Sunday, when Illinois made 18 of 64 shots.Ranked for the first time since the week of Jan. 14-20, 2013, Illinois got off to a slow start in the lone meeting between the in-state rivals this season.The Illini shot 6 of 31 from the floor (19.4 percent) and missed all eight of their 3-pointers in the first half and trailed 22-15 at halftime. The 15 points were the Illini’s fewest in a half this season and the second-fewest Northwestern has allowed over 20 minutes.NU couldn’t pull away in the first half, shooting 33.3 percent.