Mohamed Zidan's Borussia Dortmund threw away their one-goal lead to allow Bayer Leverkusen to claim a 1-1 draw in the Bundesliga on Saturday. Swiss striker Alexander Frei, who scored in the 2-1 German Cup defeat to Werder Bremen on Wednesday, put the hosts ahead nine minutes before the break. Patrick Owomoyela robbed a defender in the right hand side of the area before crossing for Frei to head home from close range. Patrick Helmes secured a share of spoils three minutes past the hour mark with a powerful shot from inside the area. Egyptian forward Zidan started the game, partnering Frei upfront for the second successive game. Dortmund manager Jurgen Klopp recently praised the harmony between the duo but Zidan hardly made an impact against Leverkusen. He was substituted in the 70th minute after a disappointing performance, making way for Paraguayan striker Nelson Valdez. Dortmund remained sixth in the Bundesliga table with 30 points as they missed out on the chance to go level with fifth-placed Leverkusen, who have 33 points. Elsewhere, high-flying Hoffenheim moved top of the table after securing a precious 2-0 home victory over Energie Cottbus. Senegalese striker Demba Ba opened the scoring in the 28th minute and new signing Boubacar Sanogo wrapped up the victory in the 63rd minute. Surprise package Hoffenheim occupy the summit on 38 points, two ahead of second-placed Hertha Berlin, who defeated Eintracht Frankfurt 2-1.