The Black Cats are still searching for their first league win of the new season after slipping up 1-0 against QPR on Saturday.
Charlie Austin fired the hosts' first goal of the new term, denying Poyet's men the chance to get off their first league win.
A frustrated Poyet lambasted Sunderland's defensive lapses and profligacy in possession, admitting he will take his squad to task ahead of their next league clash, at home to Tottenham on September 13.
"To lose that control and momentum, in those 15 minutes before the break; they made us suffer," he said.
"It's got to be a wake-up call for us really
There's no place for this.
"We put ourselves under pressure, giving the ball away cheaply in our own half."
Adam Johnson produced two perfectly weighted through-balls for Patrick van Aanholt and Steven Fletcher as Sunderland took the early initiative at QPR.
Both men failed to provide a finish to match the approach play, however, and the Wearsiders paid the ultimate price in defeat.
Austin blasted home just before half-time to break the deadlock, and despite several further half-chances Sunderland were unable to claim any points.
Poyet is still chasing several new recruits ahead of Monday night's transfer deadline, to add to his stand-out summer capture of Jack Rodwell.
Once the transfer frenzy subsides, though, the former Chelsea midfielder will relish an extended run with his squad on the training pitch.
"The timing of the goal didn't help," said Poyet.
"I don't know if it was overconfidence after a decent start, but there's no place for that at all.
"We know the numbers we've got to work with, so we've just got to get on with it now."
Source : PA
Source: PA