Originally Posted by Wolverine
With all Madara taught Obito, him becoming good enough, to not get killed by Minato, is not that difficult to comprehend.
It is when you look at the entire timeline. At most 13 months passed from the time Obito was crushed to the Kyuubi attack (Kakashi was 13 when the mission started, his birthday is in September, Kyuubi attack occurred in October of the next year (Naruto's birthday is October 10) which was 12 years prior to the start of the series when Kakashi was 26). In that time, Obito not only became strong enough to capture Kurama, but put Minato on his toes at the same time. Also, in that time, he grew 8 inches. Now, growth spurts can be an explanation, but a person doesn't grow 8 inches in the span of a year. At most, during the height of an adolescent's growth period, a male grows at a rate of 4 inches a year.