The Tigers were downed by two first-half goals against Aston Villa on Sunday and the manager has deemed it the most disappointing of his tenure
A disastrous first-half showing on Sunday saw Hull go into the half-time break 2-0 down at Villa Park thanks to goals from Gabriel Agbonlahor and Andreas Weimann.
While Nikica Jelavic diverted a header in off Aly Cissokho to give Hull hope, the damage had been done as Bruce's men ended a disappointing week with their first Premier League defeat of the new season.
The FA Cup runners-up were knocked out of the Europa League by Lokeren on Thursday and Bruce pulled no punches in his assessment of Hull's display in the opening 45 minutes.
"For how good our second half was, our first was just as bad," Bruce told reporters. "We gave ourselves such a mountain to climb with the first-half performance in particular - it was arguably the worst I've seen us perform.
"I can't remember us performing so badly. In the second half we made a game of it and on another day we could have nicked something. But I still can't get over how bad we were in the first half.
"We gifted them goals, we made mistake after mistake and we didn't get above a jog so how do you expect to win a Premier League game?
"We had so many people who performed so badly, it was a shock to me but maybe we're getting carried away with all the nonsense that's being written about us and all the rest of it. It's been a wake-up call.
"We can't wait until the second half and have me ranting and raving like some sort of lunatic to have a response. I wish we could get them in tomorrow and start working with them straight away but we can't, we've got 11 or 12 away [for international duty].
"Mind you, if they keep performing like that they won't be internationals."
Bruce acknowledged he is likely to be active in the transfer market over the next 24 hours ahead of Monday's deadline and confirmed a deal has been agreed with Irish midfielder Brian Lenihan from Cork City.
Attacking midfielder George Boyd is also in discussions with Burnley and Abel Hernandez is close to moving to the KC Stadium, although Bruce does not envisage a deal being done for Manchester United's Tom Cleverley.
"We allowed George to go to speak to Burnley, I wish him well. He got the offer of a three or four-year contract at Burnley," the Hull boss added. "I wish him well and it looks as if he's going to go to Burnley.
"We expect [the Fernandez deal] to be completed, it could be completed today."
On Cleverley, Bruce continued: "I can't see it. I don't think it's going to happen."