After a bright start, it degenerated into another abject display from the Addicks.
Charlton could not come to terms with Brentford’s five man midfield, and Guy Luzon made no tactical adjustments to counter the Bees’ dominance in the central area, that allowed Lee Carsley’s team to control the game.
Luzon started with Stephen Henderson in goal, and Patrick Bauer, Johann Berg Gudmundsson, Johnnie Jackson, Franck Moussa and Simon Makienok all came into the starting line-up.
Moussa should have done better with an early chance, and Gudmundsson and Watt also had opportunities.
Henderson was called upon to make a good stop, and Makienok and Moussa tested Button.
But it was Brentford who took the lead after 26 minutes. A pinpoint cross from the right by Alan Judge was met by a bullet header from John Swift, which gave Henderson no chance.
Former Addick, Alan McCormack rattled the bar just before the interval.
A sweeping move from deep in their own half, saw the visitors double their advantage after 55 minutes, when Judge curled the ball in from the edge of the box, after being played in by McCormack.
Charlton’s misery was compounded late on when a superb Judge pass put Lasse Vibe clear to add the third.
The defeat was a bridge too far for Luzon, who had his contract terminated after the match. Damian Matthew and David Martane were also dismissed.
Charlton: Henderson; Solly, Bauer, Sarr, Fox; Gudmundsson, Jackson , Cousins, Moussa (McAleny 60); Watt, Ahearne-Grant 76), Makienok (Ghoochannejhad 56).
Subs (not used): Pope, Bergdich, Ba, Holmes-Dennis.
Booked: McAleny 77 (foul).
Brentford: Button; Yennaris, Dean, Tarkowski, Bidwell; McCormack (sub Canós 89 mins), Diagouraga; Woods, Judge, Swift (sub Kerschbaumer 62 mins); Djuricin (sub Vibe 73 mins)
Subs (not used): Bonham, O’Connell, Gogia, Hofmann
Goals: Swift 27, Judge 55, Vibe 86.
Referee: Stuart Attwell (Warwickshire).
Attendance: 14,585