Owen Hunter had 14 points and 10 rebounds while leading South Portland (9-5) past the Knights (3-11) in North Berwick.
Gerik Bialorucki added 11 points for the Red Riots. Tyler Oliver tallied 11 for Noble, with Garrett Brown and Brandon Drake scoring 10 each.
South Portland took a 16-6 lead in the first period behind six points each from Pamba Pamba and Shippen Savidge, and four from Ryan Boles. The Red Riots extended the lead to 28-14 by the half before a fourth-period Noble rally cut the final margin to seven points.