Sean Maguire struck the winner as Preston moved up to third in the Championship with a 1-0 win at Birmingham.
In a game of few chances, the forward's 23rd-minute effort ensured North End secured their first away league win since March.
Birmingham could count themselves unlucky not to claim something from the game, however, after seeing their unbeaten run at home end.
They appealed strongly for a penalty when Maxime Colin's cross appeared to strike the hand of Ben Davies, and had an effort from substitute Alvaro Gimenez controversially ruled out for offside 11 minutes from time.
Preston had an early, albeit marginal, penalty shout when defender Harlee Dean appeared to shove Maguire in the back, causing him to fall over. But referee Stephen Martin waved play on.
North End took the lead with the first real attack.
Maguire tapped in the rebound after Paul Gallagher's low curling free-kick hit the inside of the post after beating a five-man defensive wall as well as goalkeeper Lee Camp.
Birmingham midfielder David Davis conceded the set-piece after upending Maguire following a surging run.
It was the 25-year-old's second goal in as many games and third of the season.
Birmingham's big penalty appeal came in the 56th minute. A cross from right-back Colin appeared to strike the hand of centre-back Davies in what looked like a 'hand to ball' movement.
The Blues' bench protested furiously at the fourth official but the referee and assistant were unmoved and only awarded a corner.
Blues caretaker head coach Pep Clotet made a double substitution in the 61st minute in a bid to drag his side back into the game.
Gimenez and Jacques Maghoma replaced Kerim Mrabti and Jude Bellingham to inject fresh impetus into a team that had not laid a glove on Preston for an hour.
Birmingham, who have managed just one first-half goal in the Championship this season, have the fewest shots in the second tier with 138 and it was not difficult to see why.
But the shot-shy home side had the ball in the net in the 79th minute only for Gimenez's tap-in from Lukas Jutkiewicz's cross to be ruled out for what looked like a very close offside call.
The game had belatedly warmed up and Preston responded with a chance to double their lead a minute later.
Tom Barkhuizen was put clean through with Camp to beat but he bizarrely chose to check, turn and try to pass rather than shoot when that seemed the obvious option, and the opportunity was lost.
Birmingham piled forward towards the end but the closest they came to scoring was an overhead kick from Gimenez that flew straight at goalkeeper Declan Rudd.
