Huddersfield tore Brentford apart as Jordan Rhodes struck twice against his former club to extend the Terriers' unbeaten league run to 36 matches.
Rhodes powered home a header to give the visitors the lead before Lee Novak latched on to Damien Johnson's through ball to double the advantage.
Novak's cross then found Rhodes who headed home from close range.
Gary Roberts completed the rout when he hammered home after Rhodes' effort had struck the post.
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Brentford boss Uwe Rosler told BBC London 94.9:
"We win and lose as a team, I don't blame individuals.
"For me when we switched to 4-4-2 we looked very dangerous but the second goal killed us off and after the second one we lost belief and I was not happy.
"It was difficult to take for me, we trained well this week, I didn't expect it today, the plan started well, but football is about duels."
Huddersfield Town manager Lee Clark told BBC Radio Leeds:
"We were outstanding, terrific and I'm delighted with the performance. We showed today that we are good team in every aspect of the game.
"We didn't start well, but we got into the game and started to cause them problems and scored with a terrific goal through Jordan Rhodes, then in the second-half we played the game like I want them to play, kept the ball well, we moved it and we were clinical, so I'm delighted.
"I'm delighted with every aspect. I thought there were some outstanding perfomances."