Not really luck... if you have a decent team, then it's just fun! I despise losing at Battle Frontier not for the sake of losing, but because I have to work my way through lame trainers who use NFE Pokes that one Earthquake will take down. It's boring!
I seem like a poster boy for this Poke, but Blissey is perhaps one of the best Pokes to use at BF... I'm still amazed at how this thing absorbs [Special] Attacks. Although, I feel Serene Grace Blissey is better for in game BF than Natural Cure Blissey. The later is pretty much for a professional battle with a full team.