Centre-back Tom Holmes gave Reading a 1-0 half-time lead with a spectacular overhead kick in stoppage time – his first goal for the club.
But Hull levelled 10 minutes after the interval when goalkeeper Luke Southwood allowed a long-range effort from Mallik Wilks to squirm under his body.
Reading felt they should have been awarded a late penalty when Di’Shon Bernard appeared to handle the ball under an aerial challenge from Andy Carroll but referee Steve Martin waved away their appeals.
McCann continued: “Reading had a couple of good chances but, apart from those and the goal, we could have been almost out of sight with all our opportunities.
“I was disappointed with their goal and the timing of it but, in the second half, I said to the boys ‘Can we show people what we are all about and could we show that determination in the second half to get ourselves back in the game?’ - we did that. It was a great strike from Mallik.
“Then, as we have done over the last four or five games, we had to show all that grit again.
“Particularly away from home, when they were raining in the high balls and free-kicks to Andy Carroll. He’s so strong in the air.
“With Mallik’s goal, he hit it early and I think he just caught the keeper off guard.”
Of the late penalty incident, McCann said: “I could possibly see why the referee could have given something like that. In football, you get some and you don’t get some. That’s what happened here.”
Reading manager Veljko Paunovic called for the introduction of VAR. “I just don’t understand. I don’t usually like to talk about officiating but these kind of decisions cost us a place in the play-offs last season. Today it cost us two points. That’s difficult to cope with.
“VAR would help this situation, definitely. I think there are versions of VAR in discussion, a sort of VAR Lite. This would reduce the costs and time of reviewing.
“Yes, I would like to see VAR in the Championship. When you do well, you need to have at least have the benefit of review.”
Reading: Southwood, Yiadom (Tetek 46), Holmes, Dann, Baba, Laurent; Halilovic (Azeez 57), Drinkwater, Swift, Dele-Bashiru, Carroll. Unused substitutes: Camara, Rafael Cabral, Puscas, Ashcroft, Abrefa.
Hull City: Baxter, Bernard, McLoughlin, Greaves, Longman (Elder 66); Smallwood, Docherty, Lewis-Potter, Honeyman, Wilks; Magennis (Tyler Smith 75). Unused substitutes: Ingram, Cannon, Moncur, Williams, Huddlestone.
Referee: S Martin (Staffordshire).