Bundesliga leaders Borussia Dortmund could see their advantage over Bayer Leverkusen reduced to just two points this weekend if results fail to go their way.
Both sides play on Sunday, but Leverkusen's game at Bayern Munich kicks off two hours before Dortmund entertain Freiburg.
And a victory for the side lying in second place in the table would pile the pressure on Dortmund as they attempt to build upon their five-point lead.
Whatever happens earlier in the day, Freiburg defender Pavel Krmas, who is suspended after being sent off against Hoffenheim last week, is confident the leaders will not have things all their own way.
He told the club's official website: "This is definitely a tough game. Borussia Dortmund have been playing the best football in the league all season.
"It will definitely be hard work. But we have proved that we compete with every opponent and can also cause leading teams difficulties, and hope that will be the case against Dortmund.''
Dortmund have lost just once in their last 12 Bundesliga outings - they went down 1-0 at Hoffenheim on March 12.
However, they will be without Paraguayan striker Lucas Barrios, who picked up a groin injury during last Saturday's 1-1 draw at Hamburg.
But Leverkusen are in similarly impressive form and head for Munich on the back of five successive league victories.
The weekend's fixtures get under way tomorrow night when fifth-placed Mainz attempt to maintain the pressure on Bayern in fourth when they host bottom-of-the-table Borussia Monchengladbach.
They currently trail the Munich club by seven points, and while Champions League qualification looks to be a tall order, the Europa League is well within their grasp.
However, Monchengladbach will arrive having given their survival hopes a major boost with a thumping 5-1 victory over Cologne last time out, although they remain two points adrift of both St Pauli and Wolfsburg, the sides immediately above them.
Hannover face a tough trip to seventh-placed Hamburg as they attempt to give themselves breathing space in third with Bayern just a point adrift.
Nurnburg too are on the road at Kaiserslautern, where victory would maintain their hopes of securing a Europa League spot, while Champions League semi-finalists Schalke travel to Werder Bremen.
The side which dumped holders Inter Milan out of the competition with a 7-3 aggregate victory have won three of their last four league games, but are languishing in ninth place, a staggering 27 points adrift of Dortmund.
Cologne play host to Stuttgart, while Eintracht Frankfurt head for Hoffenheim, and there is a real relegation six-pointer at Wolfsburg.
The teams currently in 16th and 17th places meet at the VfL Stadion as the home side welcome St Pauli with both on 28 points, two behind Stuttgart.