A fantastic late winner from Mark Yeates gave Parkinson's men a dramatic, but deserved, win at Deepdale, consigning Preston to their first home league defeat of 2014 in the process.
Yeates' match-winner - a superb curling effort from just outside the box - came less than a minute after Preston top scorer Joe Garner had equalised for the hosts following Rory McArdle's first half opener.
Although Preston came into the game currently occupying the second automatic promotion spot, there was no denying that the Bantams left the game as worthy victors after a determined display that had Parkinson full of praise.
Parkinson said: "We started with real intent today (Saturday). We'd spoken to the lads beforehand to tell them that we were going to come here and be positive.
"If you come to Preston and sit back, they have some quality players who will hurt you.
"From right at the start of the game, however, we were closing them down, winning corners, getting crosses in. We were perhaps unlucky not to get a second goal in that first half period.
"We knew they would throw caution to the wind in the second half. They threw Kevin Davies on and kept hitting diagonals onto us.
"Admittedly, we had to ride our luck at times, but we also had some great chances on the break as well.
"When Preston got the equaliser, it was a low moment, but it didn't last long because Yeatesy has then produced a moment of magic.
"In games like this, you need your big players to produce big moments, and Yeatesy certainly did that for us.
"It was a top class finish and we know he is capable of that."
The Preston victory comes off the back of last Sunday's F.A Cup win at FC Halifax Town and an encouraging display at home to Doncaster Rovers the weekend before.
Reflecting further on City's Deepdale display, Parkinson feels that his side's recent training ground workload is starting to pay off.
He added: "We played well against Doncaster and we were very unfortunate not to win that one.
"We built on that performance in the Halifax game and then now today's match. The lads have worked really hard and trained really well over these last couple of weeks.
"We've had no midweek matches recently so we have been able to get some good work done on the training ground. The lads have really been buying into it and I think that has been shown in the performances.
"The levels of fitness and energy in the team was very good. The ground our lads have covered today was different class."