Northern Ireland manager O’Neill is currently juggling managing the international side with Championship strugglers Blackburn Rovers until the end of the season.
Despite the unique approach of having two jobs at once, Magennis added that it will be “no problem” for O’Neill as he aims to make more history as Northern Ireland boss.
“He has been able to multitask, and he has been doing brilliantly,” the Exeter City forward continued.
“Blackburn were in a bit of disarray and he has managed to steady the ship, him and ‘Davo’ [Steven Davis].
“He is coming in with great confidence. He is a great football man and his mind for football is fantastic so for him to come here and switch it up will not be a problem for him.”
Watch Italy v Northern Ireland in the World Cup play-off on Thursday, 26 March from 19:00 GMT on BBC iPlayer, BBC One NI and BBC Three; listen on BBC Sounds and BBC Radio Ulster, and follow live text commentary with in-play clips on BBC Sport app and website.
On Wednesday, 25 March watch a special preview show with Italy and Chelsea legend Gianfranco Zola on BBC iPlayer and the BBC Sport app and website from 19:00 GMT.