Berlin (Germany), Oct 14 (IANS): With teams in the first four places set to cross swords, fans eagerly await the duels of Borussia Dortmund and table leaders Union Berlin and second-seated Freiburg turning up in Bayern Munich, which makes the upcoming weekend a Super Sunday in the German Bundesliga.

Two worlds seem to collide when the countries' top dogs face the opportunity to strike back and close gaps to the challenging underdogs as Bayern and Dortmund were two and four points behind their rivals respectively.

While a disappointing league performance is causing growing unrest around Bayern and to some extent in Dortmund, Berlin and Freiburg are riding the wave.

Pundits speak about the underdogs' realistic chances to, for the first time, qualify for the Champions League, and the title race in the national league hasn't been similarly thrilling over the past years as Bayern took the championship for ten consecutive times.

The differences between Sunday's competitors couldn't be greater when it comes to revenues and expectations.

The Black and Yellows vs Union is 420 million euros compared to 71.25. Bayern hosting Freiburg makes 611 million facing 114.9.

While titles are a must for the established clubs, feel Union and Freiburg for a reason like in the middle of an unexpected dream.

Other than their national rivals, Union and Freiburg stand for consistency with coach Urs Fischer in charge since 2018 and Christian Streich as the country's longest-serving manager (since 2012).

The club's coaching stability is coming along with steadiness on the management stage and a robust team spirit.

Union is delivering pragmatic football, at their best providing strict discipline, and a simple but robust style far from the spectacle in a 3-5-2 system.

"It's brutal to play them. You rarely find spaces," Streich said about Berlin's tactics. Only 43 percent ball possession, 203 sprints, and 165 ball contacts in the opponents' half make Union hit the lowest figures in the league.

Unbeaten in away games this season, Freiburg are counting on a highly flexible 4-2-3-1 system coming along with the team's capability to change and use dead-ball situations for scoring.

Both clubs are not only successful on the national but international stage after qualifying for the Europa League this season.

"A lot is possible for both when they keep steady," former Bayern captain Philipp Lahm said.