Classmates Diamond DeShields and Allisha Gray added 18 points and eight rebounds, and 15 points and nine rebounds, respectively. Mavunga's dominance around the basket allowed Carolina (6-2) to score 50 points in the paint against the Fighting Illini.
Sarah Hartwell scored 11 points to pace Illinois (5-3). Amber Moore tossed in 10.
"I thought in all three games this week we did a lot of great things that will make us a good team down the line," said Associate head coach Andrew Calder.
Carolina dominated the second half, outscoring the Illini, 45-19. A 36-8 run turned an eight-point advantage into a 36-point rout by the 5:42 mark with the Tar Heels leading 83-47.
Illinois was limited to seven field goals in the second half and shot 28.8 percent for the game.
DeShields and Mavunga landed on the all-tournament team for their work in three games in three days. DeShields scored 18 or more points each day, while Mavunga recorded a pair of double-doubles and has five in eight games this season.
"Playing back-to-back-to-back games early in the season is difficult," said Calder "I want to give credit to the work our players have done with strength coach Jason Beaulieu.
"Conditioning really shows up when you play on consecutive days and to be as sharp as we were today is a credit to the dedication these players have for this team. That was a critical factor in coming away with a win today."
Illinois crept out to a 17-10 lead by the 12:18 mark of the first half, but Mavunga's put back lay-in gave Carolina a 24-20 lead four minutes later, the largest lead at that point in the game for the Tar Heels.
Mavunga scored six more points in the next 2:46 to cap a 22-7 spurt, putting Carolina in front, 32-24, with 5:10 until intermission.
Hartwell did her best to keep Illinois in the game with 11 first-half points, including consecutive buckets to keep it close at 36-32, but Carolina scored the next six points to take a 42-32 lead at the break.
"This was a difficult tournament for us but we had a lot of people contributing, both from the starters and our players coming off the bench," added Calder.
Carolina hosts No. 10 Nebraska in the ACC/Big Ten Challenge on Wednesday at 6 p.m., on ESPN3.