Angry Partizan Belgrade fans pelted coach Avram Grant with lighters on Saturday and chanted his predecessor's name after the former Chelsea manager failed to get a first win after his second game in charge.
There was more serious crowd trouble across the Serbian capital when Rad Belgrade and visiting Novi Pazar fans threw rocks and flares at each other, forcing riot police to move in and delay the second half for 10 minutes.
Serbian champions Partizan, chasing a record fifth successive league title, saw their lead at the top of the 16-team first division cut to six points after a 0-0 draw against visiting Sloboda Sevojno.
But it was the behaviour of the fans, who called for Grant to be sacked and Aleksandar Stanojevic to return, that left the Israeli fuming rather than his team's tepid performance.
"Football is a game of goals and we failed to score but the players put in a great deal of effort and the fans should learn to respect that," Grant told reporters with a grim expression on his face after the final whistle.
"I don't think it was a mistake to start with just one player up front because we created plenty of chances, all big teams play with a solitary striker these days," he added.
Partizan had been held to a 1-1 draw at struggling newcomers Novi Pazar in Grant's first game in charge.
Closest rivals Red Star Belgrade took full advantage after coming from behind to earn a 3-1 win at Javor Ivanjica on Saturday and give their fans a boost ahead of the first leg of the domestic cup semi-final against Partizan on March 21.
Nigerian striker Obiora Odita gave Javor an early lead before Brazilian midfielder Evandro, Luka Milunovic and left back Filip Mladenovic turned the match on its head.
Fireworks and fighting were restricted to the terraces at Rad Belgrade's ramshackle ground, where rival fans scuffled before the kick-off and started a riot at half-time.
The trouble began after fans from Novi Pazar, a southern Serbian region populated mainly by Muslim Slavs, brandished a Turkish flag.
Riot police moved in to create a buffer zone between rival fans and there were no more problems.comments