Lennon cup final reunion for what could be O'Neill swansong

"Well done, boss."

The way Neil Lennon greeted his former manager in the main stand at Hampden after Celtic's progression to the Scottish Cup final just goes to show that old habits really do die hard.

It is more than 20 years since he was under his charge and yet he still refers to Martin O'Neill as "boss" or "gaffer".

The last time the pair were in competitive action together was also at the national stadium, with Lennon at the heart of a Celtic midfield that helped O'Neill end his first spell in charge with a third Scottish Cup triumph.

That was May 2005. Soon, professional, on-field acquaintances will be renewed.

In just over a month - and for the first time in their careers - they will be in opposing technical areas as Lennon's Dunfermline Athletic attempt one final giant-killing act against O'Neill's double-chasing Celtic.

Both men have legendary status in Glasgow's East End for their trophy-laden spells at Parkhead.

Lennon's mission may sit slightly uneasily: to make sure his old manager's farewell doesn't end with a fairytale storyline, although both men are famously ferocious competitors.

"He's been fantastic for me, both at Leicester and at Celtic," O'Neill told BBC Scotland.

"His record in management is really terrific. What a job he's doing at Dunfermline to get to the final. But there will be no old pals' act. I'm just pleased that we're in the final with him."

I might not be here without him – O'Neill

So where and when did this decades-spanning, and still flourishing, relationship begin? According to O'Neill, in Lennon's flat when the then Crewe Alexandra midfielder was just 24.

It was 1996 and the former Wycombe Wanderers and Norwich City boss was determined to sign his fellow Northern Irishman for his new-look Leicester City side.

So determined, O'Neill likes to recall, that he and his assistant, the late John Robertson, went to Lennon's apartment and refused to leave until he agreed to come to Filbert Street.

Legend has it that the management duo even stayed the night to make sure they had a firm agreement.

Lennon signed for the Foxes in February. By the summer, he and O'Neill had secured City promotion to England's top flight.

Those were heady days for Leicester as the pair won two League Cups and reached another final, with the side more than holding their own in the top half of the Premier League.

"He's been a big part of my managerial life," O'Neill, who is in his second interim spell at Celtic this season, said.

"He's done great and it's no surprise. I think he's a top-class manager. His record both as a player and manager at Celtic is quite extraordinary.

"I've got the utmost regard for him. Had I not signed him for Leicester, I might not be sitting here."