Ryan Brunt's controversial goal was enough for Leyton Orient to beat Brentford at Brisbane Road.
The 19-year-old looked offside as he poked home from close range on 75 minutes after a half-cleared long throw was lobbed back into the Bees' area.
The O's rode their luck, especially in the first half when League One's top goalscorer Clayton Donaldson was twice denied by home goalkeeper Ryan Allsop.
Both sides had penalty claims rejected after the break before Brunt struck.
Brentford dominated the opening 45 minutes and, following Donaldson's chances, were again unlucky not to take the lead seven minutes before the break.
Brentford boss Uwe Rosler's verdict
"It's very difficult to say something critical to my players. We played Leyton Orient off the park. But in the decisive moments in both boxes we need match-winners."
Paul Hayes's powerful low shot from the edge of the area was heading in before Orient defender Gary Sawyer dived full length and got enough of his body in the way to deflect the ball behind for a corner.
Bees defender Tony Craig came up for the resulting set-piece and found himself unmarked in the area, but could only nod over.
Despite the second half being more evenly matched, Brentford should have gone ahead on 51 minutes when Donaldson turned sharply before releasing a lovely reverse pass to free Harry Forrester on the left. But Hayes could not get on the end of Forrester's low cross and the chance went begging.
The Orient fans were screaming for a penalty just after the hour when veteran striker Kevin Lisbie appeared to be grabbed by Bees defender Harlee Dean as the pair tried to get on the end of Dean Cox's low cross from the right.
But referee Phil Dowd was unmoved, as he was a couple of minutes later when Hayes's powerful shot hit a retreating Ben Chorley's hand.
With 15 minutes remaining, though, Brunt - on loan from Stoke City - did enough to give Orient their second successive victory.
Nathan Clarke's long throw from the left was headed clear, but only as far as far as Martin Rowlands.
The former Brentford man lobbed the ball back into the box and after a scramble, Brunt - appearing to be standing offside - beat Simon Moore.
- 16 Allsopp
- 03 Sawyer
- 04 Chorley
- 15 Clarke
- 02 McSweeney Booked
- 07 Cox
- 08 Griffith
- 21 Cook Booked (Odubajo - 75' )
- 22 Rowlands (Smith - 85' )
- 09 Lisbie
- 10 Symes (Brunt - 61' )
- 19 Grainger
- 06 Baudry
- 11 Smith
- 14 Laird
- 17 Odubajo
- 26 Brunt
- 39 Mooney
- 21 Moore
- 05 Craig Booked
- 06 Dean
- 14 Logan
- 24 Bidwell Booked
- 04 Forshaw (Adeyemi - 74' )
- 08 Douglas
- 20 Diagouraga
- 09 Donaldson
- 19 Forrester (Saunders - 80' )
- 23 Hayes (El Alagui - 80' )
- 16 Gounet
- 03 Barron
- 32 Legge
- 02 O'Connor
- 07 Saunders
- 12 Adeyemi
- 10 El Alagui