Keegan arrived back on Tyneside with immaculate timing to see the 10-man Magpies serve up one of their most impressive performances of the season and book an FA Cup fourth-round trip to Arsenal.
The former player and manager took his seat in the directors' box 20 minutes after kick-off and at times it seemed as if he had never been away as the club's players threw off the shackles of Sam Allardyce's reign to take Stoke apart.
True, they will face far stronger opposition in the Barclays Premier League this season, and will face Bolton on Saturday with midfielders Emre, Alan Smith and Nicky Butt suspended.
But it was the manner in which they dealt with the Coca-Cola Championship promotion contenders in front of an ecstatic crowd of 35,108 which will have pleased Keegan and beaming owner Mike Ashley.
Michael Owen's first goal since October 7 started the ball rolling with just eight minutes gone and after Emre had been sent off for a challenge on John Eustace, defender Claudio Cacapa doubled the advantage 14 minutes before the break.
James Milner made sure on 68 minutes and Damien Duff's first goal at St James' with 14 minutes remaining would have been the icing on the cake had Liam Lawrence not pulled one back at the death.
In truth, the game for all-but-caretaker-boss Nigel Pearson and his players had been rendered largely irrelevant by the news of Keegan's appointment, which broke shortly before 4.30pm.
Such was the desire to share in a significant night on Tyneside kick-off had to be delayed by 15 minutes as fans flocked to buy tickets in the wake of the announcement that Keegan was on his way back.
Allardyce ultimately paid the price for not producing the required levels of excitement, but it was in abundant supply once again from the off.