Marinus Dijkhuizen was unhappy with his midfield performance as a mixed-up Brentford side were beaten 2-1 by League Two Luton.
The Bees were sloppy in possession in the first half with both Alan McCormack and Marcos Tebar guilty of losing the ball too often.
And the Dutchman is keen to see more from the midfield and gave the squad a dressing down at half-time.
He said: “I was not so satisfied by the midfield in the first half as we had a lot of loose possession.
“We spoke about it at the break and it was much better in the second half.”
Konstantin Kerschbaumer was given the night off after playing 90 minutes against Stoke, while Lasse Vibe was rested for the contest after returning home to prepare for a move to England.
Dijkhuizen feels his squad has developed well enough so far this pre-season but there is still plenty of room for improvement.
He added: “I have only known them four weeks. It's difficult to say. We played a good game on Saturday but not so good today. I hope we're at 60 to 70 per cent so we have scope to improve a lot.”
