Steve Stone told his players to make this a one-off after the young Clarets were beaten by Stalybridge Celtic at Bower Fold.
The BetVictor League Premier Division outfit struck twice in the opening six minutes and then never relinquished their grip on the game to run out 3-1 friendly winners.
And Stone admitted his side had to learn the lessons of competing against a more powerful side with the bit between their teeth.
“That’s real football,” said the Under-23s’ boss.
“I spoke beforehand about respecting the opposition, in terms of they were going to give it everything they’ve got and put the ball in behind and challenge and make it difficult and scrap for everything.
“They did that better than us right from the start and we were 2-0 down from set-plays because they put the ball in behind us and asked us questions.
“I said to the boys afterwards they wanted it more than you – so that’s a starting point for them to learn for the rest of pre-season and the rest of the season. That’s their one.”
Tunde Bayode briefly made it 2-1 with a fine goal superbly created by one of two trialists in the Clarets’ starting line-up.
But another poorly conceded goal just before the break took Celtic into clear water again.
And despite the hard-running up front of Rob Harker, the Clarets failed to create the second-half openings to threaten a comeback in a below-par performance.
"They have to learn when it's on to play and when it is to over-play," added Stone.
“The instructions I gave them at half time seemed to be ignored by inexperienced, younger members of the group.
“That’s sometimes expected, and they need to learn quickly.
“There were positives in that most of them played 90 minutes, which is ahead of schedule in what we’re trying to do, but we’ve got lots of work to do.”
The next leg of the Under-23s’ pre-season schedule takes them to Bamber Bridge next Wednesday night.