Partizan have 30 points from 11 games followed by Red Star on 25 and Jagodina with 23 after their first win over the 1991 European Cup winners in 10 league games.
The champions, chasing a record sixth straight league title, won in style after a shock Cup exit at the hands of second division Borac Cacak on Wednesday and boosted their confidence ahead of next week's Europa League clash with Inter Milan.
An early Dusan Kolarevic own goal sent Partizan on their way before youngsters Stefan Scepovic, Milos Jojic and Nikola Ninkovic found the net in a one-sided contest.
Red Star striker Ognjen Mudrinski opened the scoring against his former club Jagodina but after that it all went wrong for the home side who had defender Nikola Maksimovic sent off for a professional foul shortly after the hour.
The visitors, who had never beaten Red Star in any competition, took full advantage as midfielder Milan Djuric and substitute Dejan Djenic turned the match on its head.
Partizan host Radnicki Kragujevac while Red Star visit neighbours OFK in next round of league matches before Belgrade's big two meet in a potentially explosive derby on November 17.