Wednesday managed just a couple of worthwhile efforts on target and could have left Griffin Park on the end of a much heavier defeat but for goalkeeper Cameron Dawson.
Dawson made at least four one-on-one saves to deny Maupay, Sergi Canos, Watkins and Said Benrahma as the Bees dominated the second 45 minutes.
And Luhukay said: “I am very disappointed because it is not nice the way we played. For the first 20 minutes we were in the game and then the penalty came and we lost control and Brentford looked stronger and had moments to score more.”
The Owls cause was not helped when winger Adam Reach hobbled off in the warm-up with a knee injury, but Luhukay refused to offer his absence as an excuse.
He added: “He is one of our important players, but we cannot use losing him as an excuse because we started with 11 players like Brentford.
“Realistically we have to try to finish higher than last season. We were strong in the last two months of last season and that spirit was not there today and that is very disappointing.
“We can only play with the team we have and the players we had today and we must always have focus and concentration and that was not 100 per cent today.”