Here are some "lucky punch" quotes from fighters - you are demonstrably dead wrong on this point.
Aldo:
http://sports.yahoo.com/blogs/mma-c...still--feels-like-the-champion-173530085.html
Anderson:
http://www.mmamania.com/2013/9/25/4...on-silva-chris-weidman-ko-punch-was-lucky-mma
Cung Le:
http://www.sherdog.com/news/news/Cu...cky-Punch-in-UFC-on-Fuel-TV-6-Headliner-47277
I could go on.
The challenge with the declaration of a "lucky" punch is that you're usually working with a very small sample size so it's hard to differentiate between skill (something that can likely be re-produced) and luck (very low probability event that cannot be easily reproduced). I'll just keep working with the Conor vs. Aldo situation since it is the very definition of this problem.
1- Jose Aldo makes an aggressive lead-right bait to left-hook attack. The goal here is to draw Conor's right hand down defensively so he gets obliterated by the left-hook.
This largely works. Conor does indeed drop his right hand to parry the shot and Conor DOES get hit by the left-hook. The attack is partially successful and unlike most I don't consider this a stupid suicidal charge on Aldo's part. With a timing alteration of a hundreth of a second or two he might have landed this shot hard enough to drop Conor.
2- Conor makes a beautiful counter-left on Jose that instantly shuts the lights off. The question isn't whether there is skill involved - Conor has consistently shown he can deliver the big left on many opponents. The question is - What is the likelihood that in any given exchange that Conor drops former #1 P4P in the world Jose Aldo with a single fucking punch. I would literally take a bet on my house that Conor cannot repeat this outcome.
So, here's the crux. Normally if a fight plays out for at least 5-6 minutes you start to get a feel for who is consistently finding more success than their opponent. Who's landing more/better shots. Who is dominating the grappling. You get to see the fighter's showcase their skills and start to show who is, overall, the better fighter.
When the fight ends in 13 seconds you can be almost 100% certain that you didn't get to see enough fighting to make a good judgement call on who is really the better fighter and that the fighter who won in 13 seconds has virtually 0% chance of repeating that outcome - aka - luck.
If you had 100 fights between Jose and Conor and he lead with that exact same attack all 100x there is no chance in hell that Conor would KO Aldo all 100x.
* You'd have some fights where Aldo eats the fight, gets rocked, and continues.
* You'd have some fights where Aldo eats the fight, is not hurt, and continues.
* You'd have some fights where Aldo's left-hook clobbers Conor and he's the winner of a 13s fight.
* You'd have some fights where we'd get a Rocky-esque double KO or see two rocked fighters stumble away from each other.