Wilkinson (right) is comforted by London Irish's mascot
London Irish 38 (24)
Tries: Lea'aetoa, Russell, Mapusua, Geraghty 2
Cons: Geraghty 5
Newcastle 12 (0)
Tries: Flood, Phillips
England fly-half Jonny Wilkinson limped off injured as his Newcastle side crashed to a heavy defeat to London Irish at the Madejski Stadium.
Shane Geraghty was the main architect of Newcastle's problems, scoring 23 points for the Exiles.
London Irish went into half-time with a 24-0 lead thanks to tries from Tonga Lea'aetoa, Robbie Russell and Seilala Mapusua and the kicks of Geraghty.
Newcastle did claim two tries, but the Exiles ended as handsome winners.
The Falcons started off in encouraging form, but a Delon Armitage interception took London Irish straight up the other end and the move ended with a penalty for Geraghty.
The fly-half missed two kickable penalties soon after but then set up prop Tonga Lea'aetoa to crash over from close range.
Life got even more difficult for Newcastle with the sin-binning of prop Joe McDonnell on 16 minutes.
Tonga Lea'aetoa goes over for London Irish's first try
London Irish took full advantage, with Russell touching down after a catch and drive and Mapusua adding a third try soon after.
Wilkinson kicked three penalties in quick succession to the corner, but his forwards failed to make much impact with their rolling mauls and the Falcons trudged into half-time without a point to their name.
Newcastle's Toby Flood gave his side some hope on 61 minutes, finishing off a long spell of Falcons possession with Wilkinson adding the conversion.
Three minutes later, substitute Ollie Phillips added another try for Newcastle but that was as good as it got for the visitors.
Wilkinson was taken off with six minutes left to play, apparently nursing a hamstring injury.
Geraghty took that as his cue to score two tries in three minutes and put the seal on an impressive team and individual performance.
His first saw him break through a mass of Newcastle players to get in under the posts, and he sailed through from 10m out soon after for his sixth try of the season.
London Irish coach Brian Smith:
"All's well that ends well, we got the bonus point, which at half-time we would have suggested we would have got, but Newcastle made it very hard for us.
"We lost complete control of the game in the second half, in a 20 or 30-minute period, we couldn't get a scrum feed or a penalty and we couldn't get the ball off the pitch.
"They have got a world-class back line and they are a very skilful side and they had us on the ropes, and we are disappointed with that aspect."
Newcastle director of rugby John Fletcher:
"Jonny's just got cramp and that's why we took him off.
"Whether the cramp was anything else we will have to see, but he's icing it as obviously you would. It's too early to say, he's got cramp in his hamstring, so we took him off.
"Basically all you can do with that sort of acute injury is ice it - there's nothing else you can do for 24 to 48 hours."
London Irish: Flutey; D Armitage, Mapusua, Catt (capt), Tagicakibau; Geraghty, Hodgson, Hatley, Russell, Lea'aetoa, Kennedy, Casey, Roche, S Armitage, Murphy.
Replacements: Collins, Paice, Hudson, Leguizamon, Magne, Willis, Ojo.
Newcastle: Burke (capt); May, Tait, Noon, Flood; Wilkinson, Grindal; McDonnell, Thompson, Ward, Sorenson, Oakes, Parling, Harris, Winter
Replacements: Golding, Long, Buist, Wilson, Phillips, Dickson, Crichton.
Referee: Ashley Rowden (RFU)