That happened to me last night. Made my 5v5 arena team with a blues/greens mix of early lvl 70 gear. Started at 1500 rating, and ended the night 0-10 at around 1400 rating. All fights were against 1500+ teams, and 5 of the last 6 was against the same 1800-1850 team in full S3/S4 gear. Oh well, not like I really care about PvP anyway. I'm just in it for the freebies, even if it takes me an extra week or two per item with a lower rating.