Partizan, aiming for a record sixth successive league crown, triumphed 1-0 at struggling Radnicki Kragujevac to stay two points clear of second-placed Red Star who beat OFK Belgrade by the same score.
With three games remaining, the eagerly-awaited clash at Partizan's stadium will attract a full house and is likely to be played under tight security with the fixture having a history of crowd trouble.
"We didn't play the way we wanted but the most important thing is we won and now have a week to recuperate for the crunch game against Red Star," Partizan coach Vuk Rasovic said after captain Sasa Ilic turned in a Predrag Luka cross for the only goal.
"It's also vital our key players who were on one yellow card didn't get booked and will be available for the derby."
Former Wolverhampton Wanderers midfielder Nenad Milijas converted a second-half penalty for the hosts to keep Red Star in the hunt.
It also gave their Portuguese coach Ricardo Sa Pinto his eighth straight victory at the 1991 European Cup winners since he took over in March.
Both sides missed a hatful of chances with Red Star keeper Boban Bajkovic keeping out several stinging shots and an injury time sitter after a free kick was floated into the six-metre box.
Elsewhere, 13th-placed Novi Pazar have a chance to climb further away from the relegation zone when they entertain third-placed Vojvodina Novi Sad on Sunday.