Two goals in the last 10 minutes saw Preston grab a 2-2 draw having been 2-0 down to Bristol City at home.
That left Robins manager Gary Johnson feeling down-at-heel as he joked that referee Michael Oliver had been their opponents' "best forward".
He was referring to a decision to award North End a spot-kick in the final moments of four minutes of stoppage time. Preston captain Callum Davidson despatched the penalty kick with style to send the fans crazy.
Irvine said afterwards: "We certainly left it late. I took a chance. I am not a gambler, but took a chance by going with a 2-4-4 formation by the end.
"I wouldn't call it a master stroke; it was a case of necessity.
"I have to say I'm obviously delighted with the character that the lads showed. I was questioning it for a while.
"Instead of having courage and being prepared to take the ball, we had suddenly looked a bit nervous at times.
"When we allowed Bristol City to get a second goal it obviously looked like a long way back. On both occasions for City's goals we had comfortable possession of the ball.
"Firstly we turned a great counter-attacking opportunity for us into a penalty for them and then we gave away very comfortable possession carelessly for the second goal.
"We had the best record of coming back last year and obviously I'd rather not be behind. When it does happen, you want your players to have the mental strength, character, determination and courage.
"They answered by doubts and my questions about their levels of character very, very emphatically at the end of the game.
"But I'm not as happy as people might think I might be because I felt we should have won it overall.
"We have come back from being two goals down with very little time left and that is a positive thing.
"We certainly kept going right to the end but if the game had been going a couple of minutes longer we might have managed to win it."
Bristol took the lead shortly after the break thanks to ex-Celtic player Paul Hartley's well-executed penalty kick. This was followed around 10 minutes later by David Clarkson's simple shot into goal from Danny Haynes' cross.
Preston looked well beaten before John Parkin grabbed what appeared to be a consolation goal, firing in with nine minutes of normal time to go.
However, the penalty decision for a handball provided a grandstand finish to give Preston fans some glee.
Bristol City manager Gary Johnson admitted he was disappointed to be forced to leave Deepdale with just a point.
He said: "We were in a winning position. We rode our luck, the goalkeeper has done his job making a couple of good saves.
"We then came out in the second half looking very strong and got our two goals. We started the Preston fans going home which is always a good sign.
"At that point you have to go 3-0 or 3-1 up. We had a couple of good chances to go 3-1 up.
"I have not seen what led to the penalty to be honest. Marvin Elliott is disappointed.
"Marvin had his hands up in the air. He said he was pushed. It was in the 96th minute, (there were supposed to be) four minutes of injury time. Of course we go home disappointed but at the same time we showed a very competitive game to Preston."
Johnson added with a smile: "The referee was their best forward in the end. He blocked our clearance. That led to their second goal.
"It was a good game but we have two points lost from where we are.
"I was pleased with the work-rate, our assurance on the ball and I thought we had a lot of the ball. There were a lot of good things.
"When something happens in the 96th minute that all goes out the window. You get on the coach and start thinking how the rest of the game went.
"Sometimes decisions can work in your favour, sometimes they can go against you."