Dorsey saw Crenshaw miss on a two-point conversion pass midway through the fourth quarter, then made one final defensive stand and held on for a 13-12 victory Friday night.
The victory assured the Dons, ranked No. 13 by The Times, at least a share of the Coliseum League title and spoiled the first night football game in Crenshaw history.
Dorsey (9-0, 4-0 in league play) also ended Crenshaw's 23-game league winning streak, which included a forfeit victory over Fremont in 2001. The Cougars (7-2, 3-1) had also won the previous four games against the Dons.
Rickie Collins, who gained 43 of his 68 yards in the second half, scored on a five-yard run with 6:07 left to cut the lead to 13-12 before the Cougars' second two-point attempt of the game failed.
Aaron Huntley had 135 yards rushing for Crenshaw.
-- Ben Bolch