Sometimes genius is the ability to attain perfection, more often it is the ability to see the perfection in the imperfect. That translates sometimes into the simple understanding that sometimes the best option - the perfect solution - is to settle for the imperfect and continue.
Rabbi Nussun was a tremendous genius, but before he met Rabbi Nachman this itself worked against him, all his inadequacies ate at him and destabilized him, to the extent that he lost his drive to really prevail in Torah study.
Rabbainu instilled and imbued in him what an awesome privilege, achievement, and delight even one solitary gleaning of Torah is, and from then on Rabbi Nussun's diligence was set, he returned to studying passionately guarding and taking advantage every second, even on his travels - an extremely taxing affair in those days. He found an attainable perfection in the moment before him.
Na Nach Nachma Nachman MeUman!