BELGRADE - Police arrested 51 fans after crowd trouble marred a Serbian first divison derby between Partizan Belgrade and bitter rivals Red Star on Wednesday, Belgrade media said. Beta news agency said Red Star fans set stadium seats on fire after the game and clashed with riot police before kickoff, while Serbian television showed footage of a huge blaze in the northern tier of Partizan's ground. Fire brigades moved in and although no casulaties have been reported, the incident is likely to draw serious repercussions by the Serbian Football Federation and the authorities. The fixture has a history of crowd trouble, dating back to times when Serbia was still a part of the former Yugoslavia. In 1999, a Red Star fan was killed at the same tier in Partizan's ground after a flare was launched into the northern section from the Partizan end. the game at Red Star's ground in October 2000 was abandoned after only four minutes when rival fans invaded the pitch, fought with each other and attacked players. Defending champions Partizan won 2-0 on a warm Wednesday evening to go 13 points clear at the top and close in on their 21st league title with nine games left. Senegalese striker Lamine Diarra, the first division's top scorer, tapped in his 15th league goal of the season to give Partizan an early lead after good work by winger Nemanja Tomic. Substitute Nikola Vujovic sealed Partizan's first home win over Red Star in eight years with an 82nd-minute thunderbolt, which gave Red Star goalkeeper Sasa Stamenkovic no chance. "The title race is not mathematically over yet but we have a huge lead wth few games to go now and we are confident that we will retain the title," Partizan coach Slavisa Jokanovic told Serbian television. "It was a massive win for us after a very solid performance and I have to congratulate my players for a great team effort."