Kevin Jez hit an 18-foot jumper with 18 seconds left Wednesday night, lifting St. John's to a 56-55 playoff victory over Mackin at Carroll.

Avenging a 45-44 loss the last time the two Metro Conference powers met, the Cadets won league runner-up honors and the privilege of meeting Spingarn Sunday at Cole Field House preliminary to the city championship match between De Matha and Dunbar.

Mackin turned a three-point deficit into a three-point lead late in the final period. Moe Young connected on both ends of a one-and-one, then Kevin Black, commanding the boards all night, tapped one in and Kenny Payne closed out Mackin's scoring with two free throws. That gave the Trojans a 55-52 advantage with 43 seconds left.

St. John's pulled within one on Bob Donohoe's jumper. Mackin's Richard Crooks was called for pushing off on the following inbound pass, but Cadet Mark Townsend missed the free throw. Young repaid the favor after a Cadet foul, and Billy Barnes fed the rebound to Jez for the game-winner.

Barnes missed a free throw with four seconds left, giving Mackin one last shot, but Mark Nickens' 25-footer failed.