Newcastle manager Alan Pardew has criticised his side after they conceded five second-half goals to Fulham on Saturday.
The Magpies went in to the interval 1-0 up but by the time the final whistle was blown, they found themselves 5-2 down.
Pardew pointed to the penalty that gave Fulham an equaliser early in the second half as a turning point in the game.
"I thought the contact was minimal and the only contact that did take place was on the edge of the box," he said.
"But it got given and we have to accept that. It was our reaction to that goal that was the disappointing thing today.
"That unit at the back did not play well second half, no way near good enough in terms of the standards they've set."
Pardew also claimed that the 25 second-half minutes in which Fulham scored four goals were among the worst he had seen as Newcastle manager.
"We talked about the fact that the wind was with us and balls in behind would hold up. But without criticising individuals in our team, our second-half display in that period wasn't what we have been doing all year," he added.
"I can't think of any period in any game where we were as inefficient as we were today for 25 minutes.
"We lacked mental discipline in that second half and it cost us. Hopefully it won't happen again."
The result means that Newcastle remain in the sixth place in the Premier League, level on points with fifth place Arsenal.