Match ends, Brentford 3, Leeds United 1.
Brentford scored two late goals to inflict a sixth defeat in seven Championship games on Leeds.
Neal Maupay headed the Bees ahead after Leeds keeper Andy Lonergan fumbled Yoann Barbet's left-wing cross.
Ollie Watkins then blazed a penalty over for the hosts and Leeds levelled when home keeper Daniel Bentley missed a cross and Ezgjan Alioski headed in.
Barbet's free-kick restored the Bees' lead before Ryan Woods slotted in a late third from 18 yards.
Despite their poor recent run Leeds' defeat saw them slip out of the top six for the first time since August, while Brentford are up to 12th, three points off the play-offs.
Dean Smith's side have now won three successive games and are unbeaten in nine in the league, their longest run without defeat since winning promotion to the second tier in 2014.
For much of the game it looked like the main talking points would be the goalkeeping errors which led to the first two goals as both Lonergan and Bentley appeared to lose crosses from the left in the floodlights.
And after Alioski levelled it appeared that Brentford might rue Watkins' earlier missed penalty, awarded for Pontus Jansson's foul on Maupay, as Leeds looked to be gaining the ascendancy.
But Barbet fired in a brilliant low free-kick from wide on the right to restore the home side's lead before Woods scored his first goal in 59 games with virtually the last kick of the game.
Brentford boss Dean Smith told BBC Radio London:
"I felt we deserved the win. In the first half we were very good and probably deserved to go in two goals up but we missed the penalty.
"Their subs changed the game, put us under pressure for the first 25 minutes of the second half and Dan made a mistake and they got the goal.
"But we got back on the ball, went and pressed a bit higher in the last 20 minutes, and got some joy out of that.
"There is a big togetherness here and we need to harness that and keep it going. We have a lot of belief in the way we play so we need to make sure we don't drop off the work ethic."
Leeds head coach Thomas Christiansen:
"I believe we deserved much more. I saw the strength in the team. We made two changes at half-time and the team went out, believed in the possibility to turn the result around and we were almost able to do it.
"In this league, when you make individual mistakes, we get punished. We had several opportunities to score, but when you're in this negative situation then it's more that our chances go out than in.
"We need to work hard, we need to prepare well and motivate the players. They proved in the second half that they are able to perform and win."
- 5BjellandSubstituted forMephamat 45'minutes
- 29BarbetBooked at 90mins
- 8YennarisBooked at 68mins
- 19SawyersSubstituted forMokotjoat 73'minutes
- 11WatkinsBooked at 45mins
- 9MaupaySubstituted forVibeat 80'minutes
- 14O'KaneBooked at 45minsSubstituted forHernándezat 45'minutes
- 10AlioskiSubstituted forGrotat 80'minutes
- 9LasoggaSubstituted forRoofeat 45'minutes
- 21SáizBooked at 90mins
- Stuart Attwell
- Shots on Target
Second Half ends, Brentford 3, Leeds United 1.
Goal! Brentford 3, Leeds United 1. Ryan Woods (Brentford) right footed shot from outside the box to the bottom right corner. Assisted by Kamohelo Mokotjo.
Attempt blocked. Ollie Watkins (Brentford) left footed shot from the left side of the box is blocked. Assisted by Lasse Vibe.
Attempt missed. Luke Ayling (Leeds United) header from the centre of the box is close, but misses to the left. Assisted by Pablo Hernández with a cross following a set piece situation.
Samuel Sáiz (Leeds United) wins a free kick on the right wing.
Foul by Kamohelo Mokotjo (Brentford).
Samuel Sáiz (Leeds United) is shown the yellow card.
Yoann Barbet (Brentford) is shown the yellow card.
Foul by Ronaldo Vieira (Leeds United).
Ollie Watkins (Brentford) wins a free kick on the right wing.
Goal! Brentford 2, Leeds United 1. Yoann Barbet (Brentford) from a free kick with a left footed shot to the bottom left corner.
Foul by Kalvin Phillips (Leeds United).
Florian Jozefzoon (Brentford) wins a free kick on the right wing.
Foul by Luke Ayling (Leeds United).
Ollie Watkins (Brentford) wins a free kick on the left wing.
Substitution, Leeds United. Jay-Roy Grot replaces Ezgjan Alioski.
Substitution, Brentford. Lasse Vibe replaces Neal Maupay.
Nico Yennaris (Brentford) hits the bar with a right footed shot from more than 35 yards.
Samuel Sáiz (Leeds United) wins a free kick in the defensive half.