Trailing 1-0 to Chris Willock's 16th-minute opener, the Tigers finished the first period of their maiden home Championship outing of 2021/22 in the ascendancy and picked up where they left off after the break.
Josh Magennis' header drew a fine stop from Seny Dieng just before the interval, then Keane Lewis-Potter (twice) and Lewie Coyle came close to levelling matters within 10 minutes of the resumption.
City's clearest chance of the afternoon arrived before the hour-mark when substitute Matt Smith slotted confidently beyond Dieng, only for Rob Dickie to come to the visitors' rescue with a superb goal-line clearance.
And shortly after that key moment in the contest, Lyndon Dykes put Rangers 2-0 up and in complete control.
“We struggled again at the start of the game and the goal they scored was sloppy but we grew into the game and the last 10-15 minutes [of the first half] we were in the ascendancy," McCann reflected.
“We took that into the second half and I thought we started excellent. I thought we were gonna equalise and at that point, if we had have done, I thought we could have gone on and won the game.
“There’s Keane’s chances and Matt Smith has done brilliantly to win the ball back and nutmeg Dieng and then there’s the unbelievable clearance from their centre-half.
“I really do feel that if one of those goals had gone in, the pendulum would have swung and we probably could have come away with three points.”
Hull midfielder George Moncur was sent off almost immediately after Dykes’ 68th-minute strike, a moment which effectively ended the home side’s hopes of mounting an unlikely comeback.
McCann said he wasn’t sure whether the red card for his new signing’s challenge on Dominic Ball was deserved, and also felt his side should have had a penalty, but insisted that referee Matt Donohue was not the reason the Tigers ended up empty-handed at the MKM Stadium.
“I’ll need to see it back," he said of Moncur's dismissal.
"From the angle where the camera is that our analysts use it doesn’t look great and it’s right in front of the referee, but George is not the type of player to go in and try and hurt somebody.
“Hopefully I can get another angle and see whether it was and whether he’s made contact and we’ll take it from there because obviously we don’t want to lose George for three games.
“I’ll reserve judgement on that until I see a different angle.
“The handball is a blatant penalty. How the referee hasn’t given that is beyond me, but at that stage it’s 3-0.
“But look, the referee didn’t lose us the game today, it was our concentration levels, but we will learn and improve.”