PREVIEW - Unbeaten Hoffenheim take on unpredictable Dortmund

BERLIN ( Reuters) - Little-known Hoffenheim and Champions League winners Real Madrid share an unlikely record this season as the only teams in Europe's top leagues that are still unbeaten.

With Borussia Dortmund the visitors on Friday, Hoffenheim will not know what to expect from their Bundesliga rivals.

Dortmund have sparkled in Europe this season, topping their Champions League group ahead of Real to book a last-16 spot. But domestically they have been inconsistent, winning three of their last nine league games.

The Ruhr valley club's erratic run has seen them slip to sixth, eight points behind leaders Bayern Munich despite their 1-0 win over the champions, the only league defeat suffered by the Bavarians.

"Dortmund are a bit difficult to calculate," Hoffenheim captain Niklas Suele said. "Especially away from home (they) seem to have problems.

"But that changes little in terms of the amazing quality that the team has especially in attack with (Pierre-Emerick) Aubameyang and ( Marco) Reus. We have our work cut out."

Apart from Bundesliga top scorer Aubameyang, who has netted 15 times this term, Dortmund have also relied heavily on Reus' late scoring abilities.

The Germany international looks to be back to his best after a six-month injury absence, rescuing a draw at Real with a last-gasp strike earlier this month before doing it again in the draw with Cologne last week.

Hoffenheim's three-man back line has worked wonders for young coach Julian Nagelsmann, with his team showing remarkable flexibility during a game, changing formations easily and surprising opponents as they have climbed to fourth.

"The coach often allows us to switch systems during a match," said Suele whose team survived a relegation battle last term. "This is an ability we acquired during pre-season.

"That way our opponents have trouble estimating what to expect and we can always adapt to their game."

Bayern, top on goal difference from promoted RB Leipzig, travel to relegation-threatened Darmstadt 98 on Sunday.

Leipzig entertain third-placed Hertha Berlin, who are six points behind their hosts, on Saturday.

(Reporting by Karolos Grohmann; Editing by Tony Jimenez)