Although BG9 isn't necessarily the "best" battle group anymore, it certainly had possibly the most exciting finish to season five WoW power leveling. Unlike other battle groups like Cyclone EU with multiple teams (four in this case) sharing the rank one position, the Americans on Bloodlust went down fighting.

Zilea and Niero had a long monopoly on the rank one position on the ladder for several weeks. After many sighs of regret and many people looking toward the dark days of Zilea referring to himself as a Deadly Gladiator, to many people's surprise, Zilea and Niero ended up tanking around 100 rating on the last night somehow and losing out on the title to none other than Noxn herself playing a hunter in full hateful gear. So how exactly did this happen WoW power leveling? Apparently no one even knew until the next morning when Noxn posted in this thread on AJ to clarify the accusations of win-trading with Threk's team:

"It's really a long story that I want nothing to do with. Basically, don't grants me, we don't deserve this title if we do get it. I'm not going to lie to anyone, but the long story short is:

threk/whiteshadowz lost 1-2 games on purpose for 7 points each, we didn't know they were doing that until the second game (although we knew that they weren't playing up to ability in the first game, we just shrugged it off since they almost killed us at some point anyway).

Whether their intention were to get Zilea to queue so THEY could play him and THEY could get DG, or if their intentions were to get Zilea to q so he would stop dodging every team up there, I don't think it really matters. Player may speak to NPC without any WoW power leveling.

Anyway, we did negate these points by zoning into an arena and losing on purpose, but by that time, Zilea had already queued and lost to random low teams and we were too far ahead for him to catch up about WoW power leveling.

Basically, we did get all but 14 of the points legit, and we lost over 14 (I believe, I forget the exact amount) BUT, there is nothing to say that when we were 14 points below, that we wouldn't have lost a string of games, thus allowing Zilea to sit on his rating and get DG without playing at all.

The entire night got completely up and I'm so sick of this end of the season drama that happens to me every season."

Apparently after catching up to Zilea in rating and pressuring them into queuing, Zilea and Niero proceeded to lose not only to Threk's Shaman/Warlock team but also losing several games in a mirror against Mesmerized's DK/Paladin team from Frostmourne.