BERLIN - Title challengers Schalke 04 host arch-rivals Borussia Dortmund in Germany's fiercest derby on Friday with bad feeling still lingering from their meeting earlier this season.
Leading pair Bayer Leverkusen and Bayern Munich, separated only by goal difference at the top, both have tricky home games, with Leverkusen facing Cologne on Saturday and Bayern taking on Hamburg SV on Sunday.
Although Schalke and Borussia have attempted to dampen down their rivalry off the field, there is little love lost between the players.
Schalke goalkeeper Manuel Neuer gave an interview this week in which he said that Dortmund players had wrongly accused him of elbowing an opponent following Schalke's 1-0 away win in September, courtesy of a Jefferson Farfan goal.
"All the television pictures have shown what happened and what didn't," he told the weekly magazine Sportbild.
"Some of the Dortmund players have damaged my reputation. Their comments were absurd and not nice."
Neuer, expected to be in Germany's World Cup squad, was also angry at Dortmund complaints that he celebrated in front of their fans.
"I had cups of beer thrown at me and was spat at," he said. "But the same people complained that, after the final whistle, I simply raised my arms in front of them."
Off the field, the clubs made a joint appeal to fans for a peaceful match, asking them to avoid, among other things, violence, racist chances, stealing flags and banners from rival fans, provocative marches and the use of fireworks.
"Only when these basic rules apply will the clash between Borussia Dortmund and Schalke 04 be what it is meant to be - the Bundesliga's most exciting derby," said their statement.
"Nobody wants a lovey-dovey derby but anyone who wants to turn the rivalry into outright hostility has to be shown where the boundaries lie in no uncertain terms."
Borussia Dortmund will be without their top scorer Lucas Barrios because of suspension.
Third-placed Schalke, who have 45 points from 23 games, dropped four points behind the leading pair when they conceded two goals in the final 20 minutes and lost 2-1 at VfL Wolfsburg last Sunday.
Borussia are a further six points back in fifth and know that victory could put them back in contention for a Champions League spot.
Leverkusen, still unbeaten as they attempt to win their first league title, host a Cologne side smarting from a 5-1 home defeat by VfB Stuttgart last Saturday.
A win or draw in Saturday's match would allow Leverkusen to set a Bundesliga record of 24 unbeaten games, overtaking Bayern's tally from the 1988/89 season.
Bayern's coach Louis van Gaal was involved in an angry exchange with a television presenter during a touchline interview after last weekend's draw at Nuremberg.comments