A solitary goal inside the first four minutes from debutant David Dowson handed Brentford their first defeat of 2008, 1-0 at Chesterfield.
The 19-year-old striker, on loan from Sunderland, wriggled free of the Brentford defence after picking up a Jack Lester pass and lashed home from 14 yards to settle the match early on.
In a game which threatened at stages to entertain but never really did Brentford huffed and puffed but could not breach the home defence and headed back to London with a first defeat in ten matches.
Brentford started an ultimately frustrating afternoon badly; Peter Leven fired a free kick over early on and shot wide soon after while Phil Picken also had a try from distance soon after Dowson's opener.
The visitors were struggling to make an impact on the home defence, not helped by an over-officious referee who ensured the game was very stop-start, and it took them 25 minutes to create an effort of note.
When it came Gary Smith should have equalised, he picked up a neat Alan Connell pass and bore down on goal but Chesterfield stopper Barry Roche saved with his legs.
The Bees began to get on top as the first half went on and the match briefly came to life with end-to-end action but Aaron Downes could have put the hosts two up when he headed a Jamie Lowry free kick wide from close range.
Matthew Heywood had a header cleared, Glenn Poole sliced an effort wide and Roche turned a Ryan Dickson free kick over the bar at full stretch.
Connell fired wide on the turn and Ricky Shakes headed straight at Roche from 15 yards after the Chesterfield goalkeeper failed to gather a Dickson cross.
But Brentford couldn't get level before the break and the second half proved to be no better for the visitors.
In fact, with injuries forcing the substitutions of Heywood, Osei Sankofa and Nathan Elder, the second period could be considered to be worse.
The Bees pushed for an equaliser, Elder almost turned home a Robert Milsom cross just before his exit and Connell flicked a header inches over the top but chances were few and far between at either end.
Jamie Winter shot over the top for the hosts, Ben Hamer smothered at the feet of Lester and the same player fired over.
Even with five minutes of stoppage time Brentford couldn't find a way back into the game although that is not to say there were 300 incident free seconds.
Connell shot wide for The Bees and moments later appeared to be kicked in the back by Chesterfield central defender Janos Kovacs while he lay on the ground while Lowry was perhaps fortunate to escape with a yellow card after what looked like a two-footed tackle on Karleigh Osborne.
The visitors could not get the goal they wanted and had to head south bruised and beaten.
Chesterfield: Roche; Picken, Kovacs, Downes, Hartley; Lowry, Winter, Kerry, Leven (sub O'Hare 85 mins); Dowson (sub Fletcher 67 mins), Lester
Subs (not used): Niven, Cooper, Ward
Bookings: Lowry (88 mins)
Brentford: Hamer; Sankofa (sub Mousinho h/t), Osborne, Heywood (sub Charles 72 mins), Dickson; Shakes, Smith, Milsom, Poole; Connell, Elder (sub Reid 65 mins)
Subs (not used): Simon Brown, Stone
Bookings: Milsom (52 minutes) (second of season)
Written by Chris Wickham