Defender Mats Hummels scored twice in the second half to help Borussia Dortmund beat Arminia Bielefeld 2-0 on Saturday and move level on points with leaders Bayern Munich. It was the first time since 2010 that the 31-year-old centre back managed two goals in a league game. With 73% possession in the first half, Dortmund, who were missing injured striker Erling Haaland, had the upper hand but carved out few clear chances. It was only appropriate that they scored with a scrappy goal from Hummels, who pushed the ball over the line with his knee at the far post in the 53rd minute. The 2014 World Cup winner headed in his second from a Marco Reus cross in the 71st before being taken off injured 15 minutes later. Dortmund are level with leaders Bayern, who beat Cologne 2-1, on 15 points ahead of their clash next week. RB Leipzig, on 13 points, travel to Borussia Monchengladbach later on Saturday.