FridayDortmund     vs    Bremen    8pm SS3BERLIN. Coach Jurgen Klopp has admitted he is wary of Friday’s opponents Werder Bremen as Borussia Dortmund aim to maintain their 100 per cent record to stay top of the Bundesliga.Bremen and Dortmund are two of the five German league teams to have won both of their opening games leaving Borussia top of the table only on goal difference.Defending champions Bayern Munich, UEFA Champions League side Bayer Leverkusen, who host Borussia Monchengladbach on Saturday, and Mainz 05, who are home to VfL Wolfsburg the same day, are the other three Bundesliga times with 100 per cent records.Bremen have won both their matches under new coach Robin Dutt with 1-0 victories away against promoted Eintracht Braunschweig and home to Augsburg respectively having flirted with relegation last season.Bremen last lifted some silverware when they won the German Cup in 2009, but Klopp said there is too much talent in the Bremen team to take them lightly at Dortmund’s Westfalenstadion."There is a lot of attacking potential slumbering in this Bremen squad, so we have to be very careful,” said Klopp with Bremen expected to give Argentinian striker Franco di Santo his debut after signing from Wigan Athletic a week ago.