The Lilywhites had occupied second place in the table for months and went into the final game of the season at relegation-threatened Colchester on Sunday with a one-point advantage over MK Dons in the race for automatic promotion.
However, it was the Milton Keynes club who finished runners-up behind champions Bristol City as they romped to victory against Yeovil and Preston lost 1-0 in Essex.
The untimely loss was a first in 19 league games for Simon Grayson's men and left them in the play-offs once more.
Cook believes Preston will arrive at the Proact Stadium for Thursday's semi-final first leg keen to make the most of their second chance at promotion.
"They will have been hurting after what happened but Simon is a very good manager and he will have them ready," said Cook.
"I'm sure he'll be reminding his players that they still come into this game in unbelievable form
How many teams go 18 games unbeaten at this stage of the season and don't get promoted? It's a bit of a unique situation they find themselves in.
"But t he problem with being on a good run is you know it can't last forever
The hugely disappointing thing for Preston will be that it ended right at the final hurdle
"Simon will have picked them up and all players want to do is go out and play - and win
That's all they will be thinking about on Thursday - not what happened at the weekend."
Preston's play-off record makes for grim reading
The Lilywhites have been involved in nine play-off campaigns over the years, losing them all
North End have been beaten at the semi-final stage on six of those occasions - most recently last season when they were knocked out by Rotherham
Grayson thinks it is about time that particular statistic was laid to rest
"The record is there to be broken," said the Preston boss
"We are sick of hearing about it
We've got to embrace it
They (the fans) could be negative and disappointed but my glass is half full
"The players are certainly determined to do something about it
Why can't we get to Wembley and get promoted? It's a fantastic way to go up
"Everybody has to believe we can do it
We've proved all season we are one of the best teams in the division
"We can't affect what has happened in the past, we can affect what happens on Thursday and Sunday."
Source : PA
Source: PA