what being a good league player actually means

http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/1608565503/204586889?tab=stats i was down in lane because he chose to poke instead of cs so i got ahead in cs, i let him push to tower all game and chose my times to roam and when i could do what so despite him being fed early game saying "i beat you 1v1" well yes but that made you lose the game because i out performed you while you got 1 kill on me