A replay a week on Wednesday will pay off another chunk of Palace's £30million debts and the way Neil Warnock's side scrapped no-one should write them off reaching the quarter-finals just yet.
How cruel football can be.
It looked as if Darren Ambrose had given Palace the cup shock they craved when he fired the strike of his life past goalkeeper Brad Friedel from more than 30 yards.
The Palace faithful sang 'We're going to Wembley' and manager Warnock was a picture of animation on the touchline. And they looked good value for the optimism as Villa struggled to conjure an attacking threat in a lacklustre second half.
But then came Petrov's winner three minutes from time which leaves Palace hoping they can cash in on another televised encounter to bring in another £250,000.
Delight: Darren Ambrose celebrates after putting Crystal Palace 2-1 in front
To say Palace were up against it in this tie was an understatement.
The club went into administration a fortnight ago with thosestaggering debts. The players' futures are uncertain, manager Warnockdoes not know if he will be in a job from one week to the next and thecanteen lady has not been paid for two months.
There have been lots of beans and toast on the menu at the club'sBeckenham training ground but you cannot fault the spirit in the side.
And for long periods in an entertaining, at times pulsating cup tie,they gave as good as they got. As good as Warnock had promised, infact, when he predicted they would not go down without the mother ofall scraps.
Ambrose up front was a constant threat. Neil Danns was also a menaceand if Danny Butterfield could not conjure up the six-minute hat-trickwhich dispatched Wolves in the last round then he epitomised thebuckets of sweat shed by the south London team.
Celebration time: James Collins reacts after equalising for Villa in the first half at Selhurst Park
But give Villa credit. Martin O'Neill paid Palace the respect offielding his strongest side with Emile Heskey up front and StewartDowning and James Milner in midfield.
And Villa dominated much of the possession.
But it was Palace who took the lead and when it came after 24 minutes it came from an unlikely source.
Austrian defender Johnny Ertl had never scored for Palace in twoyears at the club. But he might well never have had a better deliverycome his way, a corner swung in by Ambrose which homed in on Ertl'sbald pate.
A quick flick of the neck and the ball flew past goalkeeper Friedeland the cup upset appeared to be on, even if the goal did come againstthe run of play.
Heads up: Johannes Ertl scores the opening goal for Palace
If Danns' crisp shot had also found its way past Friedel then Villa would have been in trouble.
As it was Villa composed themselves and announced their intention to scrap just as hard as their Coca-Cola Championship rivals.
When the equaliser came it had the mark of England quality. It was also a carbon-copy of the Palace goal.
This time it was Downing who threw in an inswinging delivery fromthe right and Villa defender James Collins rose above everyone to headhome from inside the six-yard box.
It was no more than Villa deserved, although the last action of thefirst half saw Friedel scrambling away a 25-yard thunderbolt of afree-kick from Ambrose.
Villa should have taken note, especially when Ambrose lined up another in he 69th minute.
This one was further out, some 30 yards or more, but the strike waseven better this time, arrow straight and it was past the despairingdive of Friedel in the blink of an eye.
What a wonderful strike. What a way to win a football match. Exceptit did not. Because Petrov swooped to get Villa out of jail. Theybarely deserved it.
ASTON VILLA FC