Sunderland boss Sam Allardyce admits the lack of "understanding and discipline" from his side is a major concern after going down 6-2 to Everton.
Sunderland, sporting a new 5-3-2 formation, started brightly but were pegged back by Gerard Deulofeu's soft goal before Arouna Kone smashed home a fine effort just past the half-hour mark.
Jermain Defoe got one back before the break, with Steven Fletcher equalising five minutes into the re-start. It then went badly downhill, very quickly, for Sunderland, with the Black Cats conceding three goals in seven minutes on their way to a 6-2 defeat.
Allardyce said: "I'm obviously concerned about the lack of understanding in certain periods of the game and the team.
"Particularly when we got back to 2-2, nothing wrong with what we had been doing up to then, apart from we gave away a very soft first goal away.
"That could easily have been avoided. The second was a bit of a cracker from Kone.
"But the goal just before half-time and the chances we created first half gave me some encouragement to say if we get the second, then we keep it tight lads, and play the game out and frustrate them.
"When we got the second, we attacked, attacked, attacked for the third and didn't get it and within seven minutes had tossed the game away.
"We allowed Everton to score three very silly, sloppy goals from counter-attacks they didn't have to work very hard for.
"That lack of discipline and understanding in seven minutes has really concerned me, on the basis that we should have been satisfied with the 2-2.
"We should have frustrated Everton and then maybe we would have got on the end of a counter attack and scored another. They were on the back foot when we got to 2-2.
"That sums it up for me, a lack of understanding at certain points of the game. What to do, how to do it, when to do it.
"We did it the wrong way today and gave them the opportunity to play on the counter attack and breeze through us and score three goals in seven minutes."