User blog comment:Eduardovongola/Renji Overpower/@comment-24099400-20140102061708

Another fact is that Renji has been fighting and holding his own with a handicap this whole time after his skirmish with Byakuya. He's been constantly fighting with a broken bankai not at its full potential. Just as it was revealed with Kenpachi, and Ichigo, although by different means he hasn't been fighting with his full potential for nearly the entirety of the series until now.