"Luck is opportunity meets preparation". That's a definition that a lot of people place on luck, and within the context of mixed martial arts it makes sense. In a sport where anything can happen, there are so many ways to win (and lose), and you will see an infinite amount of endings to a fight. Sometimes it comes down to who capitalizes first and who is able to take advantages of any opportunities that arise.
Chris Weidman has been branded lucky twice against Anderson Silva, despite winning all four rounds in which they fought one another. Nonetheless, Weidman brushes aside the seemingly derogatory context in which some people put on the word "luck" with regards to him. He has his own definition for luck and is happy to be called lucky within that context. It's a great tool anyone can use. The meaning of words and things people say about your is up to you. Reality is subjective and you place meaning upon it.