The former Celtic manager has discussed what brought him to Parkhead 16 years ago.
O'Neill moved to the Bhoys in 2000 after an impressive stint at Leicester City and became one of the Glasgow club's most successful managers in recent times.
When the Northern Irishman arrived, the Hoops had just finished 21 points behind the Gers in the Scottish title race, and had won just a single league title in the previous 12 years.
O'Neill brought the glory days back to the club, however, and in his five-year tenure they won three championships amongst a total of seven major trophies, which included winning a first treble since 1969 in the manager's first season at the club.
The current Republic of Ireland manager left a stable and successful side at Leicester to move north of the border, and he has admitted that a primary motivation for that switch was to be the manager who finally helped the club knock Rangers off their perch.
O'Neill told the Scottish Sun: "I loved Celtic. I wouldn’t have left Leicester for anybody else. Did I want to go to Celtic? Yeah I did, because they were having a tough time against Rangers and I thought: ‘I can put this right.’
"It was what I wanted to do. I wanted to take on that challenge and see if we could wrest those championships away from Rangers, and it was just a magical time. I loved it."
Though he stayed just five years, the transformation O'Neill brought to Celtic surely cements his status as one of the club's greatest ever managers.
The former Aston Villa boss boasts the highest win percentage of any permanent Bhoys manager in history at 75% compared with the 70% of Jock Stein, and only Stein and Willie Maley have led the club to more trophies.