Shakespeare said that "some are born great, some achieve greatness and some have greatness thrust upon them."
Former Barcelona manager Pep Guardiola was an exceptional player, but to be considered great, he would need to be beyond exceptional, he would need to have the kind of talent that comes only once or twice in a generation, he would need to possess the the kind of quality that you instantly recall when you are listing the best player in that particular position.
So as a player, maybe not so much but as a manager, there seems to be a growing consensus that he is indeed great. If he was to retire now his trophies alone in 4 years match up with the greatest managers many of whom have careers stretching around 20 years. His widely admired Barcelona side has many arguing that this Barcelona is the best team in history. It would seem obvious that Guardiola has achieved greatness given the 13 titles in 4 years, perhaps 14 if his side manages to beat Bilbao, however, the point that his greatness was largely thrust upon him looms large over his record.