Manek had a season-high 26 points when he was ejected in the second half.
Manek threw the elbow while blocking out Sochan for a rebound. Moments earlier, Manek hit a 3-pointer that gave the eighth-seeded Tar Heels a 25-point lead against the defending champs.
Sochan fell to the court as a referee whistled a foul on Manek. The flagrant foul ruling and ejection came after a review.
Sochan tangled with North Carolina center Armando Bacot in the first half and again shortly after Manek was ejected. Each drew a technical for excessive contact. Sochan was penalized for the first incident, Bacot for the second.