Disappointed Burnley boss Sean Dyche admitted an experienced line-up had come up short as the Clarets crashed out of the Carabao Cup.
Dyche made 10 changes to his starting XI for the second-round tie against League One Sunderland at Turf Moor.
But Burnley still boasted eight full internationals in their side - and despite leading through a 12th-minute Jay Rodriguez goal ended up on the wrong end of a 3-1 defeat to suffer another early exit from the competition.
Sunderland, with eight changes of their own as they concentrate on a promotion push, equalised through Will Grigg before the break.
And the Black Cats then booked a third-round trip to Sheffield United as an “unacceptable” five minutes at the start of the second half saw the Clarets concede twice more.
“The reality of football is delivering a performance,” said a candid Dyche, whose side has now fallen at their first hurdle in the competition in six of the last seven seasons.
“If you don’t deliver then it’s irrelevant who are you are playing against. In the second half there weren’t enough people actively taking the game on.
“And if I’m really honest – and I’ve told them this – if they look when you’re picking a team and ask, 'why am I not playing?' Well, that’s why!
“The last half an hour is why, because you lay down a marker in those games.
“In those games we’re looking for big characters and big performers. I thought Chris Wood did that. He looked a real handful and how we should have looked for the second half.
“A few stuck at it, to be fair, and we took Azza (Aaron Lennon) off as a precaution because Johann almost definitely won’t be ready for the weekend.
“But collectively that’s a very strong group and I’m expecting that group to perform tonight and they didn’t in the second half.
“The first five minutes of that second half was unacceptable for a group as experienced as I had out there.
“Those players have been good in training and the standard has been very high. But all that goes out the window if you’re not ready to perform.”
The Clarets twice hit the post after Rodriguez’s first goal back in Burnley.
But after an impressive opening spell they failed to respond to Grigg’s equaliser before goals from Tom Flanagan and George Dobson completely turned the tide.
“I thought we were in complete control in the first half hour and just made a mistake they capitalised on," added Dyche.
“Up until then we played very well, kept the ball, probed and asked questions and should certainly have been two up at half time.
“But it does go to show you the clinical edge in football is the important part in both boxes.
“Even after conceding we were still in good shape and then the first five minutes of the second half, from a very experienced group, is unacceptable.
“The first one they get is a ricochet and the second one is mystifying from a very experienced group of players all standing on the six-yard line.
“I don’t want to dis-credit Sunderland, but we didn’t do enough overall to win the game and that’s my biggest disappointment because that is an experience group and one I believe in.
“Equally, on the second-half showing that’s why the (Premier League) team is playing at the minute. It’s as simple as that sometimes.”