David Moyes admitted he would have been "disgusted" with himself as a player if he had made some of the mistakes West Ham made against Brentford.
The Hammers' Brentford curse struck again after Nathan Collins condemned them to a 3-2 defeat on an unlikely afternoon of firsts in west London.
Defender Collins scored his first goal for the club after Jarrod Bowen became the first player in Premier League history to score in each of his side's first six away matches.
There was also a first goal in 35 matches, and 14 months, for Brentford forward Neal Maupay.
Unfortunately for West Ham, it was a first Premier League win - or even point - against the Bees which eluded them. Thomas Frank's side have the hoodoo over the Hammers having won all five meetings since they were promoted.
"We weren't talking about anything weird and wonderful," said former centre-half Moyes.
"We've found that we've not dealt with things which as a player I would have been disgusted with myself for not being able to deal with them much better.
"I don't think my teams do that. That is why I am annoyed that I've come here and not been able to defend when put under pressure."
Maupay headed Brentford into a 10th-minute lead with his first goal since he scored against West Ham in September 2022.
West Ham equalised through a stunning volley from Ghana winger Mohammed Kudus and were ahead after 26 minutes through Bowen's strike.
But a glaring miss from Michail Antonio before half-time proved costly as West Ham fell foul of two Brentford crosses, with an own goal from Konstantinos Mavropanos and Collins' fine header giving Brentford a third straight win.
"The first goal was 'Keystone Cops'," added Moyes. "If you see that today, how can you win if you don't deal with those moments?
"The second cross comes from (Bryan) Mbuemo and we should have dealt with that, then a cross to the back post and Collins gets it.
"We're talking about small things, but small things lead to bigger things. We didn't deal well enough with the small things."
Brentford climbed above West Ham after a third straight victory and a 14th London derby without defeat.
"If feels of course very good," said Frank. "Every win in the Premier League feels fantastic and coming back from 2-1 down, against a good team, and also a good performance makes me a happy man.
"I'm smiling, I'm so pleased for Neal. The last three weeks he was showing more and more in training with the sharp touches, the good finishes, more and more confident, getting up to his best level.
"The players were really celebrating Neal's goal, and that tells you a lot about the group. A goalscoring run? That would be nice."
*copy from Press Association.
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