It's a matter of knowing MegaLuke's failings.
He's fast and hits like a truck, sure, but he's also frail as fuck, with 70HP/88Def/70SpD, and weaknesses to Fighting, Fire and Ground.
Do you -really- think he's so invincible as to have nothing that will one-shot him (given that most builds will use 4 HP/Def EVs to focus on Speed and [Special] Attack)?
All you need is to live one attack and then make the ground a little unstable or turn up the heat on him, and he gives up.
Salazzle can outspeed and Will-O-Wisp to neuter physical sets (the majority because of 145 Atk vs. 140 SpA), and if it's a special set, there's always Flamethrower...
>>31542815It depends on who moves first. M.Blaziken will kill MegaLuke if he outspeeds (and with Speed Boost, it's very likely), but Luke wins if he moves first.