By Karolos Grohmann
BERLIN, Feb 7 (Reuters) - Schalke 04 are with their backs to the wall when they travel to leaders Bayern Munich on Saturday (1730 GMT), with a prolonged slump in form risking to derail the Champions League competitors' once sparkling season.
Established as the main title rivals to Bayern at the start of the campaign, Schalke, who topped their Champions League group, have imploded since late last year with one win in their last nine games to drop to sixth place.
Their fans were jeering and whistling after last week's home defeat to bottom-placed Greuther Fuerth, adding more pressure on coach Jens Keller, who took over from Huub Stevens just before the winter break, and his team.
Keller has so far failed to turn their fortunes around with only one win in three games since the Bundesliga restart in mid-January.
The departure of playmaker Lewis Holtby to Tottenham Hotspur last week, has further compounded problems, with their midfield looking out of sorts against Fuerth.
The absence this week of several players who are on international duty has also not helped.
"It is understandable that our fans are frustrated. We are now obliged to pull ourselves out of this situation," said midfielder Roman Neustaedter.
"We have to work together to do this. If everyone shows what they can do then we will pull ourselves out of this situation," he said. "We have to keep working hard to get back to the road of success."
Schalke, who take on Galatsaray in the Champions League Round of 16 later this month, could be without forward Klaas-Jan Huntelaar, who was replaced in the Netherlands squad prior to Wednesday's friendly against Italy with an eye injury.
He will undergo further tests to determine whether he will be fit in time for Saturday's game, Schalke have said.
The mood could not be more different a few hundred kilometres further south in Munich, where Bayern enjoy a 12-point lead at the top following a record-breaking campaign so far and look set to end a two-season title drought.
With three wins and three clean sheets in all games since the league restart, Bayern tightened their hold on first place, having conceded just seven goals in 20 matches so far.
"We do not want to let off. We want to continue like that because everything is in our own hands," Croatian striker Mario Mandzukic, whose two goals last week in their 3-0 win over Mainz 05 sent him top of the Bundesliga scorers' list with 14, told reporters.
"Up to now everything is going according to plan," he said.
Champions Borussia Dortmund, on 39 points after their own fine start to the year with three wins, will look to strengthen their grip on second place with victory over visitors Hamburg SV (1430).
Bayer Leverkusen, a further two points behind in third place, travel to Borussia Moenchengladbach (1430). (Editing by Alison Wildey)