Table-toppers Middlesbrough stretched their winning run in the Sky Bet Championship to five games with a 1-0 victory at Brentford, due to a goalkeeping mistake from David Button.
The Bees goalkeeper punched a second-half Boro corner high into the air, slipped and could only look on as the ball rolled over the line.
It was harsh on the Londoners who stood toe-to-toe with the league leaders and for long spells looked the better side.
Alan Judge, a target for Sheffield Wednesday, curled a snapshot just wide as the hosts started on the front foot.
Denmark international Lasse Vibe should have put Dean Smith's side ahead two minutes later when he capitalised on a Daniel Ayala slip to race goalwards only to be thwarted by 'keeper Dimi Konstantopoulos.
David Nugent wasted a carbon copy chance midway through the half when he latched onto a slack Toumani Diagouraga backpass, but Bees keeper Button was equal to his low effort.
Boro always looked dangerous on the break and Cristian Stuani's smart volley after a neat pass from Nugent was well blocked by Button.
At the other end Judge forced a full-length save from Boro's keeper with a dipping 20-yard drive before Sam Saunders' free-kick on the half-time whistle was tipped over to safety.
After the break Brentford were by far the brighter and looked to impose themselves on the visitors, Maxime Colin bursting into the Boro box only to see his cross palmed away by Konstantopoulos.
If it was a good night for the Greek keeper, it was one his opposite number will want to forget when his 61st-minute howler gifted the points to Aitor Karanka's men.
His high punch into the swirling wind looped above the bar and dropped over the line, Ayala applying the finishing touch to give the dubious goals panel something to think about.
Once they took the lead Boro defended for their lives against wave after wave of attacks from the home side, but always looked potent on the counter with Nugent and Albert Adomah a constant threat.
The result means it is now 817 minutes since Middlesbrough last conceded in the league, and apart from a few goalmouth scrambles as Brentford ditched their passing game to go long ball, their resolute defence never looked like being breached.
Substitutes Sergi Canos and Marco Djuricin both caused Boro problems, but every time the ball dropped in the visitors' box Brentford found themselves surrounded by defenders.
Brentford boss Dean Smith said:
"I'm disappointed with the result but as I've said before we can only control performances and the performance was very good.
"If we continue to look after our performances the results will follow. The performance tonight would have been enough to beat many sides in this division.
"Boro are a good team with good players and we more than matched and at times looked marginally better than them."
Middlesbrough manager Aitor Karanka said:
"When you are top this kind of thing happens in your favour. We have been really lucky today because to be fair in the first half Brentford had three chances and we have made two or three mistakes.
"Sometimes you pay for those mistakes but when you are top of table the luck can stay with you. We were lucky because in the first half I thought Brentford played really well."