Arsenal have learned mistakes from last Champions League clash with Borussia Dortmund says Mertesacker The German believes the Gunners will be less naive this time around. Arsenal’s Champions League group couldn’t be much closer heading into the tie with Borussia Dortmund, with the two clubs and Napoli tied on six points. The two teams met at the Emirates Stadium a fortnight ago, when a late Robert Lewandowski strike sealed a 1-2 win for the Germans. The central defensive partnership of Laurent Koscielny and Per Mertesacker has been praised this term, but they were found wanting in that match and the German international says the Gunners have learned from their mistakes. “I think the team have to take their lesson but we are still good enough to compete with last year’s finalists,” Mertesacker told theclub’s website. “Both teams know that we are capable of beating each other. We have to be aware in Dortmund because it’s even harder to play there. “Two years ago we just managed to draw there, we were very lucky so that will be a tough challenge. “But when you look at the numbers from Tuesday’s game we are capable of achieving something special and we are good enough to go there and win.” The 30-year-old is likely to start with Koscielny once again at the Westfalenstadion, but will have to be aware of the attacking threat posed by Lewandowski, Marco Reus and co. Dortmund made it to the final of the top European tournament last season when Bundesliga rivals Bayern Munich beat them at the final hurdle. Despite losing Mario Goetze to Munich, the Yellow and Blacks still look strong and recruited Henrikh Mkhitaryan and Pierre-Emerick Aubameyang this summer.