The Latics, who are through to the LDV Vans Trophy Northern semi-finals and the FA Cup third round where they are set to meet Premiership neighbours Manchester City, took their superb form into the league to leave Chesterfield totally out-played.
It took only three minutes for Oldham to begin the rout as their striker Kevin Betsy played a through ball to Chris Killen who got behind the visiting defence to shoot low into the corner from 10 yards.
Chesterfield hit back when former Boundary Park youngster Mark Innes forced a good save from Leslie Pogliacomi, but they were soon further behind thanks to a 19th minute penalty.
Killen won the decision when his burst into the box was halted by the challenge of centre back Steve Blatherwick.
And Killen dusted himself off to score his second of the night and continued a purple patch in front of goal by sending keeper Carl Muggleton the wrong way.
Oldham continued to dominate and Betsy twice fired off target before half time.
Betsy made amends for his earlier wayward finishing when he made it 3-0 to Oldham in the 55th minute.
The Seychelles-born forward latched on to a Killen header 20 yards out and drove his shot just inside Muggleton's left hand post.
Only seven minutes later Oldham made it four with a quality strike from on-loan Birmingham City midfielder Neil Kilkenny.
The teenager was on the end of a smart move and stepped inside his marker before shooting into the bottom corner from 10 yards.
Chesterfield gained some consolation for their defeat with 14 minutes left as half-time substitute Caleb Folan arrived at the near post to tap in a long throw.