Olympiakos and Panathinaikos, the country’s two most popular clubs traditionally pack in fans for their encounters. But they may be forced to play their upcoming league clash to an empty stadium because of the outbreak of violence before last Monday’s game between Olympiakos and visiting Larissa fans. A sports tribunal has summoned front-runner Olympiakos to a hearing over trouble that preceded its home match. The unrest continued during play. Olympiakos fans attacked some 800 visiting Larissa fans with various objects – including stones, bottles, glasses, lighters, and seats – and also tossed a flare onto a train transporting Larissa fans to Karaiskaki Stadium. Olympiakos won the match 4-0. The Piraeus club, the defending champion, holds a one-point lead over AEK after 13 rounds of play in the Greek first division’s 16-team competition. Panathinaikos is third, nine points behind the leader. A fan ban for an Olympiakos-Panathinaikos clash, with either team as host, is unprecedented. The two teams are scheduled to meet in the new year, three rounds from now. Olympiakos overcame heavy tribunal punishment last season to hold off its rivals and rake in the club’s eighth league title over the past nine seasons. The Piraeus club – keen to make the most of its brand-new stadium, which was also used for the Athens Olympics – played several games to empty stadiums last season. The club has yet to be sanctioned this season. Though pundits believe the extent of Monday’s trouble will most likely lead to monetary sanctions for Olympiakos, the possibility of a fan ban cannot be ruled out. At Panathinaikos, the club is desperately looking for improvement and stability after a series of disappointing results in domestic and European competition. The team was recently eliminated from the Greek Cup by second-division club Ergotelis. But the woes did not end there. Last week, Panathinaikos traveled to Germany looking for at least a draw against Werder Bremen, which would have assured the Greek club third place in the group and a consolatory UEFA Cup berth, but was annihilated 4-1 instead. Panathinaikos has also fallen behind in this season’s title race. The disappointing form has prompted widespread protest among organized fans who have been calling for the resignation of coach Alberto Malesani. Club boss Yiannis Vardinoyiannis has so far resisted, opting instead for a longer-term view of the crisis. Vardinoyiannis, it is believed, wants to allow the Italian to carry on with his task and make his assessment at the end of the season. Panathinaikos, sidelined by Olympiakos’s domination of Greek soccer for nearly a decade now, has made countless coaching changes over recent seasons to little avail. The club won a league title two seasons ago. A far better record than rival Olympiakos in European competition has offered some consolation.