Keegan's first success in his second spell at St James' Park produced the first step to safety - on a day when defeat was unthinkable. Keegan's return had previously brought three points from eight league games as the Toon Army saw their beloved team slide towards the drop zone.
Yet despite no wins in 13, Keegan stood by the side that fought back with a Michael Owen goal to salvage a 1-1 draw at Birmingham last Monday.
Ironically, United's last win was a last-minute Joey Barton penalty success at Fulham just before Christmas.
Fulham went into the match full of confidence having taken four points from their last two games.
But Roy Hodgson's side had not won on their travels for 30 matches since winning at Newcastle last season and all told had gone 64 games without stringing together back to back Premier League wins.
And it was Newcastle that got off to a dream start with Viduka firing in his sixth goal of the season after just seven minutes.
The build-up was excellent with Nicky Butt spreading the ball wide to Geremi, who then picked out Viduka, who thumped in a left-footed drive to beat Kasey Keller from just outside of the box.
Jimmy Bullard brought a great save out of Steve Harper just 30 seconds later.
A long ball down the left then found Obafemi Martins who forced a stunning save from Keller.
The corner was cleared off the line by Danny Murphy and from the follow-up Abdoulaye Faye saw a spectacular overhead kick sail narrowly wide.
Harper then did well again to hang on to a Bullard shot, before a tame header from Owen just six yards out left the England striker holding his head in disbelief.
Martins had a goal disallowed in 67 minutes before Newcastle sealed the issue seven minutes from time.
Once again Geremi supplied the cross and Owen made amends for his earlier miss by stealing in to head in goal number eight for the season.