Chesterfield are through to the Johnstone's Paint Trophy final at Wembley after winning 1-0 at Oldham in the Northern area final second-leg to seal a 3-1 aggregate victory.
Oldham dominated most of the game, but veteran Jack Lester sealed the Spireites' success with a late goal.
The 36-year-old striker notched on 88 minutes, bundling into an empty net from close range after a defensive blunder between Cisak and Jean Yves Mvoto.
Oldham were denied by the woodwork after less than three minutes when Shefki Kuqi raced on to Robbie Simpson's pass and crashed his shot against the post from 12 yards.
Filipe Morais and Chris Taylor both brought saves from Chesterfield goalkeeper Tommy Lee, but the home side wasted a string of first-half chances.
Drew Talbot should have scored for Chesterfield just after the restart, only to fire straight at keeper Alex Cisak, but the excellent Lee again did well to thwart Morais and Kuqi.
Lester then produced his late show to send Chesterfield to a final against either Swindon or Barnet, who complete their southern area final on Tuesday, February 7.