Nick Martinelli capped a 27-point night by hitting a scoop shot with two seconds remaining to give Northwestern a 77-75 win over Southern California on Tuesday in Evanston, Ill.Northwestern (13-10, 4-8 Big Ten) capitalized on visiting USC playing without its scoring and assists leader, Desmond Claude, jumping to a lead it held nearly the entire game.The Wildcats’ advantage grew to as many as 15 points midway through the second half, but the Trojans (13-9, 5-6) battled back behind Clark Slajchert’s best game with USC.Slajchert scored 24 points, his most since posting 32 as a member of the Ivy League’s Penn Quakers last February. Slajchert shot 4-for-4 from 3-point range, including his last attempt with USC trailing 75-71 and 29 seconds remaining.Northwestern’ Blake Smith fouled Slajchert on the successful shot, and Slajchert converted the free throw for a game-tying four-point play.The sequence set up the game-winner. Martinelli drove baseline, attracting a double-team but getting the step between the two USC defenders. Martinelli created enough space for the lofting shot that snapped the Wildcats’ three-game losing streak.Taking the court without Claude, who played through a knee injury in the Trojans’ win over then-No. 7 Michigan State on Saturday, USC also got an uneven performance from Saint Thomas. He dished eight assists and grabbed eight rebounds, but he scored just four points and committed four turnovers.