Newcastle boss Dean Richards hit out after his Falcons side blew their chance to go second in the Premiership.
Richards accused London Irish’s Tom Parton of diving in an incident which led to his fullback Tom Penny being sin-binned.
The yellow card decision cost Falcons their victory chance as Irish took the opportunity to turn a narrow six-point lead into a commanding 16-point margin.
And despite the visitors pulling back to within two points once Penny returned, Irish had enough in the bank to seal only their second win of the league campaign.
Richards said: “For the first 65 minutes we couldn’t control the game, where we played it, how we played it and it came back to bite us.
“And when their guy took the dive on the yellow card we didn’t readjust to that as well. We didn’t react to being a man down.
“The question has to be asked why there wasn’t an HIA with the way he was rolling on the floor. I’m sure PRL will question why there wasn’t.”
Exiles boss Declan Kidney leapt to the defence of Parton, taking issue with the suggestion his player had exaggerated his reaction to get Penny binned.
“If someone is alluding to our player feigning injury I would be upset with that,” he said. “I would object to that.”
On a cold and wet afternoon in Brentford, the home side raced into a 14-0 lead with Agustin Creevy and James Stokes scoring early tries.
Kidney had picked a forward pack boasting 407 international caps and it paid off, despite Ben Stevenson pegging back a try just before half-time.
Then came the yellow card controversy, stalling Newcastle’s momentum and allowing Irish to add a third try through Curtis Rona.
Sam Stuart and Gary Graham levelled the try count as Falcons refused to go quietly but it was too little too late and Motu Matu’u put the issue beyond doubt two minutes from time.
IRISH - Tries: Creevy, Stokes, Matu’u. Cons: Jackson 4. Pen: Jackson.
NEWCASTLE - Tries: Stevenson, Stuart, Graham. Cons: Hodgson 2. Pen: Hodgson.
