Hertha Berlin succumbed to their sixth straight defeat in 2012, although there were plenty of positive signs for their new coach Otto Rehhagel in a narrow 1-0 loss to league leaders Borussia Dortmund at the Olympiastadion. Rehhagel takes over as Berlin coach tomorrow and he followed the game from his home in Essen, but apart from the result, he will have been encouraged with what he saw. The home side, led on the touchline by Rene Tretschok and Ante Covic following the dismissal of Michael Skibbe last weekend, wasted numerous chances against the defending Bundesliga champions, who claimed a fifth successive victory thanks to Kevin Grosskreutz\'s 66th-minute goal. Dortmund forward Lucas Barrios missed the only two openings of a tight opening half-hour, first heading straight at Thomas Kraft and then failing to connect with a cross from the right as the ball appeared to hit his standing leg. Berlin\'s first chance came when Dortmund defender Mats Hummels made the first mistake of a poor game on his part in the 36th minute. However, Raffael was unable to take full advantage as he robbed the German international of possession but was denied by the legs of Roman Weidenfeller. The second half opened up with a good chance for Berlin as Adrian Ramos played the ball into the path of Patrick Ebert, but he slid his shot just wide of the far post. Another mistake by Hummels allowed Raffael to spread play to Ebert, but his low cross was just too far in front of Ramos in the 53rd minute. Dortmund took the lead almost against the run of play midway through the period. Robert Lewandowski\'s header was saved instinctively by Kraft, who pushed the ball onto the crossbar, but the rebound fell for Grosskreutz, whose overhead kick went in with Kraft this time unable to keep the ball out. Hertha Berlin responded well with Raffael missing a good chance to level ten minutes later when he failed to gain full control of the ball and Neven Subotic was able to recover and block the striker\'s shot.