So, during Obito and Kakashi's fight in the Kamui dimension, Obito gets a hole in his chest. After watching the episode, most of the viewers commented that Obito "was defeated" even though he had the Rinnegan. But wasn't it because Obito "let" Kakashi win to undo Madara's Seal (as we see in chapter 675, Obito gets to know about the seal and wishes to undo it) and become the Ten Tails Jinchuuriki? Also, I wanted to know that would Kakashi (a non-Uchiha and a non-Senju) have been able to actually defeat Obito? Because during their fight, Obito didn't use Izanagi or even one Rinnegan ability (even though, just moments later, he seals the Ten Tails inside him with the Rinnegan). I am compelled to say this, but Obito's abilities are no joke.
Please provide a convincing answer to explain exactly what happened during the fight and what would've happened if Obito was really serious.