Reading dominated the match for long periods but came away with no reward for all their possession as good defending and a large slice of luck left David Lucas' goal unperished.
At the final whistle an ecstatic Craig Brown commented: "It was a nail-biter to the finish.
"I thought we shaded it overall. They had one or two chances in the first half but then so did we. David Healy had a great opportunity and Cresswell had a header before he scored.
"Reading had one effort come off the bar, that is a break that we have not had all season. We've been on the receiving end of things a bit, but I've got to commend the lads for today's display.
"Some weeks ago we played Norwich at Deepdale and battered them but came out with nothing. But today we came in after a much more competitive game with all three points.
"We had a much better second half in terms of defensive stability, the first half was a bit ragged. I have to commend our goalkeeping. David Lucas came in after a long spell on the sidelines, he was very assured."
The Preston boss was full of praise for the visiting Royals too who have adapted well to First Division football and currently lie 12th in the league.
"I think that Reading are one of the better teams in this League. They are like Preston were two years ago, having come up from Division Two with a winning mentality - taking the league by storm.
"They are not a fashionable side but are as good as many sides in this Division."