The Tigers are just four points outside the relegation zone and have conceded six goals in two league games.
QPR, who moved into the play-off positions, were much the better side for long periods, but they had to do it the hard way when Jarrod Bowen’s half-volley put Hull in front after 21 minutes.
But once Ryan Manning equalised 60 seconds before half-time an away victory felt inevitable.
Hull substitute Josh Magennis scored in stoppage time to make it 3-2, but 21-year-old Ebere Eze had left such a deep imprint upon the game – earning and scoring penalties after 78 and 88 minutes – that it was always going to be a consolation goal.
McCann said: “I thought it was a good goal from Jarrod to put us in the lead. We could have gone in 2-0 at half-time but we let them get that goal before half-time. In the second half, I thought we were disappointing. I don’t think we kept the ball well enough, probably for most of the game, really.
“We kept turning the ball over too quickly and that gave them a foothold in the game and didn’t give us a chance.
“We know we were nowhere near where we can be. We didn’t get going. It’s always concerning when you lose, of course it is, but we’ll not dwell on it too much.
“We’ll look at it and analyse it on Monday – as a group and with the staff. We’ll make sure we try and improve and get from it.
“He (Eze) is excellent, but I’m disappointed with us.”
Hull City: Long, Lichaj, Burke, Tafazolli, Elder, Stewart, Bowen, Honeyman (Toral 77), Irvine, Grosicki (Bowler 84), Eaves (Magennis 62). Unused substitutes: Batty, Ingram, Pennington, Da Silva Lopes.
Queens Park Rangers: Kelly, Rangel, Leistner, Barbet, Manning, Scowen, Cameron, Samuel (Pugh 62), Chair (Amos 84), Eze, Wells (Hugill 62). Unused substitutes: Lumley, Kane, Ball, Mlakar.
Referee: T Harrington (Cleveland).