Alkaizer is one of the best Diablo III players out there, sitting at the number one spot with his Barbarian on the Season 1 leaderboards and now — as this video proves — he has claimed this position with his Crusader as well. Pretty cool for a solo player.
In this segment, you can watch him clear a Rank 41 Greater Rift, a very high level dungeon where you only have 15 minutes to reach the endboss. He finished it in under 13 minutes, without any trouble.
What's even cooler is that he isn't facing zombies or any of the weak enemy types from Act 1, but relatively hard ones. Being lucky with weak enemies spawning in the dungeons helps a lot of players gain a top spot on the leaderboards, but that didn't happen in this case.
Rank 1 NA Croosader [YouTube]