Kristoffer Ajer struck the decisive penalty in the shoot-out to give Celtic the trophy after an epic 3-3 draw with Hearts in which the Edinburgh side fought back from behind twice to take the match to sudden death penalties.
However Celtic triumphed with the final kick of the regulation five to land the 2020 William Hill Scottish Cup, complete the 2019-20 domestic treble – the club’s fourth in a row.
An emotional Lennon could be seen staring into the sky, savouring the firework display and ticker-tape that followed his side’s trophy presentation and his former manager, O’Neill, who signed his fellow Northern Irishman as a midfielder from Leicester City 20 years ago, urged him to make the most of the achievement.
O’Neill said: “I’m delighted for him. He’s taken a lot of stick in recent months. It’s really uncalled for because we're seeing the 12 th successive trophy of which he's been a large part of in many aspects - I really can’t believe it and it saddens me he is under that sort of pressure.
Speaking on BBC Scotland’s coverage of the delayed cup final at Hampden, the treble-winning Celtic manager added: “Michael [Stewart, fellow BBC pundit] mentioned the word respite but it's not respite anymore - go on and enjoy, it's a great evening for him.”
The match ended 2-2 after 90 minutes before Leigh Griffiths and Josh Ginnelly exchanged extra-time goals.