Irvine said: "Stats are great, but you have to look a bit deeper than say that's four without a win. We could turn that around.
"I think we have to bear in mind two of the teams were West Brom and Middlesbrough, both of whom came down from the Premiership and kept their squads intact.
"I think a draw was a fair result. I don't think we really deserved to win. I don't think either team did enough to deserve winning the game though.
"Obviously I am disappointed, I was hoping to win. It isn't like the Middlesbrough game a week ago where you think it's terrific we managed to get a point in the death."
Irvine was not troubled over a possible second-half penalty for his side when the referee pointed to the spot, only to realise the linesman had already flagged for offside.
Irvine said: "I looked at the linesman fairly early and didn't get too excited when I saw his flag.
"There were contrasting systems of play in the game. There were times when Palace's system was dominating. I thought in the second half ours got on top of theirs.
"We started the game okay, then probably towards half-time they got up a little bit of momentum. We didn't clear the ball."
Preston had taken a 35th-minute lead thanks to a swerving Ross Wallace 20-yard free-kick that beat a six-man Palace wall on its way past the keeper.
That was cancelled out two minutes later as Darren Ambrose turned sharply just inside the 18 yard area and fired a cracking shot into goal. Keeper Andy Lonergan got a hand to the ball, but it was unstoppable.
That gave Ambrose his eighth goal of the season in league and cup games.
Irvine, a one-time Crystal Palace player, said of the goals: "From a spectator's point of view, they were both very good goals. I felt that theirs could have been prevented.
"It was something we highlighted as a threat in our preparations during the week."
Richard Chaplow had a golden opportunity to wrap things up for Preston six minutes from normal time, but his shot drifted a yard wide, following Wallace's cross.
The Preston boss added: "I expected them to at least work the goalkeeper in that goal move. He is a good finisher.
"I was surprised he missed the target. It was our best move of the game and would have been a terrific goal if we had got it."
Palace have now gone four games without a win, but have suffered just one defeat in eight matches.
Eagles manager Neil Warnock admitted: "I love coming to Preston, especially when we get a result.
"We are not on a bad run. I can't fault the lads. The manager can only ask the team to give everything and they do give everything.
"The game was a bit scrappy. I felt we started really well. There were some good performances in that first 15 minutes.
"We lack a little bit of quality up there, but we are trying hard in difficult circumstances.
"I thought Preston troubled us at set pieces in that first half an hour, but I think we did very well.
"The ref gave a penalty. It's the kind of penalty you get against you at Preston that you don't get against you at Palace. I think it was harsh, he was pushed in the back.
"Fortunately for us the linesman saw the offside and he told him straight away. At first I just thought he had flagged for the penalty.
"They were decent today, the linesmen, spot-on."
Warnock acknowledged that Ambrose had delivered a fantastic goal to put them back into the game.
He said: "He's just improving every week - he's a bit like old wine. He plays with a smile on his face.
"I have a joke with him while he is playing, there is a good rapport.
"He has the freedom to shoot when he wants. He's quite capable of shooting from anywhere. He very rarely gives the ball away.
"We have not got a 20 or 25 goal player. It is hard coming to Preston, they bully you at times and you have to compete.
"Alan has done a great job here. The trouble for Alan is that he does so well that expectations rise every time."