GARY O'Neil says the errors Cherries made leading to two of Tottenham Hotspur's goals were "so avoidable".
Cherries squandered a two-goal lead to lose 3-2 at Vitality Stadium, with goals from Ryan Sessegnon, Ben Davies and Rodrigo Bentancur, cancelling out a Kieffer Moore brace.
The final two Spurs goals came via set pieces, including Bentancur's stoppage-time winner.
"Really disappointed with the nature of the goals, because there are mistakes in there that will cost you at this level," O'Neil told the Daily Echo.
"So as hard as the boys worked, as committed as they were, as well as they stuck to the gameplan, if you make little slips in key areas from set plays or whatever it may be, the boys will find out that you can be punished, especially against world-class opposition."
He added: "There were some errors from us in there. Spurs are a big threat from there (set pieces), so we’d obviously worked hard on some stuff.
"There was a couple of errors in their corner goals from us, which is disappointing."
Asked further how disappointed he was with the nature of the goals conceded, O'Neil said: "The two set-play goals especially, because there are errors in there that are so avoidable.
"And obviously there’s an error in the build-up to the first one as well.
"So, disappointed. If they score from a moment of brilliance or something that you haven’t covered, then it is easier to accept.
"But when they come from something that you’ve worked hard on, it’s obviously disappointing."
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