Sir Alex Ferguson was in attendance at Celtic Park as Aberdeen completed a second-half comeback to secure a point against the Scottish champions.
The former Aberdeen boss watched on from the stands hosts took an early lead on Saturday with a quick-fire double from Japanese duo Reo Hatate and Kyogo Furuhashi.
But Jimmy Thelin's side embodied the spirit of Ferguson's time at the club and drew level courtesy of goals from Ester Sokler and Graeme Shinnie to end Celtic's perfect domestic start to the campaign.
Sir Alex Ferguson watched Celtic play host to Aberdeen just days after his ambassadorial contract at Man United was axed
Sources insist the meeting was entirely amicable and that Ferguson, who will keep his title as a non-executive director, remains a close friend of the club who will always be welcome at Old Trafford.
However, the termination proved hugely controversial among prominent figures in the game, with Graeme Souness calling the decision 'disgraceful' and insisted it was of indicative of Ineos not understanding 'how football really works'.
United legend Eric Cantona was also scathing in his criticism, and accused United's football ownership of a 'lack of respect' for the most successful manager in the club's history.
Prior to his historic reign at Old Trafford, Ferguson had earned a reputation as one of Europe's top coaches during his eight-year stint in charge of Aberdeen.
The Dons were the last side to break the Glasgow clubs' hegemony on the Scottish top flight, when Ferguson led them to victory in the 1984-85 campaign.
Ferguson also secured Aberdeen's two European honours during his time at the Pittodrie Stadium, the European Cup Winners' cup and the European Super Cup, both in 1983.