Two goals at the start of each half from top scorer Ched Evans sealed the points as the Bees failed to seriously test visiting goalkeeper Steve Simonsen.
Wales international Evans’ first came after just six minutes when he latched on to a long ball and lofted the ball over defender Harlee Dean before smashing home from 12 yards.
He stretched the Blades lead six minutes into the second half courtesy of a goalkeeping blunder from Brentford’s rookie goalkeeper Simon Moore. His goal kick went straight to Evans, who raced clear and rounded him before slotting home.
Evans might have had a hat-trick when Moore dashed from his box and attempted to head clear, but he missed and the ball fell invitingly at the Blades’ striker’s feet only for him to drill it wide.
Brentford rarely looked like clawing their way back into the game and came closest when Myles Weston tested Simonsen with a curling effort from the edge of the box.