Keegan was forced to watch in horror as his side went nine games without a victory following his emotional return to St James' Park in January.
But after seeing his side beat Fulham 2-0 last weekend, Keegan's team produced a vintage display to demolish a poor Tottenham outfit.
Darren Bent had fired Tottenham into the lead, but Nicky Butt, Geremi, Michael Owen and star performer Obafemi Martins ensured it was a memorable day for Keegan and the travelling supporters.
Newcastle almost got off to a dream start on five minutes following a mistake by Jonathan Woodgate. The ball fell to Habib Beye who fired his shot against the bar.
Seconds later Martins turned Alan Hutton on the edge of the box but saw his shot saved by Paul Robinson diving low to his left.
Robinson came to Tottenham's rescue once again on nine minutes when he made an even better save to keep Joey Barton's fierce drive out.
After a slow start Tottenham came back into the game and almost broke the deadlock on 11 minutes. Jamie O'Hara's corner picked out Woodgate whose header was well-saved by Steve Harper. The rebound fell to Robbie Keane but he fired the ball wide of the post.
The home side got their noses in front on 26 minutes. Steed Malbranque's cross fell to Bent who rose above Abdoulaye Faye to head the ball past Harper and into the corner of the net.
But Newcastle refused to lie down and grabbed an equaliser on the stroke of half-time. Geremi played the ball to Butt whose shot completely eluded Robinson in the Spurs goal and flew into the corner of the net.
Barton was desperately unlucky not to put Newcastle in front on 49 minutes when his shot from the edge of the box struck the outside of the post.
But Keegan's side were rewarded for their early dominance of the second half when Geremi curled a free-kick past the stranded Robinson in the 52nd minute.
It should have been three for Newcastle on 63 minutes when Didier Zokora gave the ball away. Mark Viduka saw his shot superbly saved by Robinson and from the resulting corner Martins was also denied by the former Leeds shot-stopper.
Owen added a third for Newcastle two minutes later. Martins made a great run down the right and played the ball to Viduka whose superb back-heel picked out his strike partner and Owen made no mistake striking the ball past Robinson.
Martins sealed the victory for Newcastle with seven minutes left when he raced into the Tottenham half and took the ball past Teemu Tainio before slotting the ball past the hapless Robinson.