A second half penalty from João Pedro gave Xisco’s Watford the points at Deepdale.
The Lilywhites restricted the visitors to very little on the night, but the decision to award the spot kick just after half-time proved the pivotal moment.
Manager Alex Neil had recalled Scott Sinclair and Jayson Molumby, with Ryan Ledson missing out through injury and Greg Cunningham moving to the bench, with a switch to 4-3-3.
And it was the home side who carved out much the better of the chances in the first half, frustrating the high-flying visitors to no real opportunities.
With just 11 minutes on the clock a glorious chance to go ahead came when Ben Whiteman opened up the Hornets defence with a lofted ball that found the run of Ched Evans. The striker did superbly to chest down and control, but with Daniel Bachmann advancing, he was unable to keep his left-foot driven shot down and it beat the ’keeper, but also the cross bar.
The North End No.26 was involved again six minutes later, with good forward play, after a long ball up from Jordan Storey. He held the ball up well and turned the Watford defender, before driving down the right side of the penalty area and driving a shot just wide of the right-hand upright.
The game remained goalless until the interval, but five minutes into the second half referee Tony Harrington changed the game when he adjudged Tom Barkhuizen to have fouled Pedro in the penalty area after ball across the box by Ken Sema.
The Golden Boys’ No.10 got up and took the spot kick himself, Daniel Iversen going the right way, but the powerful strike took the ball into the bottom left-hand corner.
A chance to level things up came just before the hour mark. A brace of corners in quick succession, the second an inswinger from Daniel Johnson on the right, was met by the again impressive Liam Lindsay, who got a good head on it, but couldn’t keep the effort down.
Three players were added, with two combining with seven minutes left to almost bring a chance for an equaliser. An Anthony Gordon free kick from the right, bounced around the box and Emil Riis found space to drill a shot goalwards. It was blocked and should have been a corner to PNE, but was not awarded and despite some more late pressure the visitors held on to take the win.
PNE line-up: Iversen, Lindsay, Browne (c), Johnson (Potts, 79), Storey, Hughes, Whiteman, Molumby, Evans, Barkhuizen (Gordon, 62), Sinclair (Riis, 72). Subs not used: Ripley, van den Berg, Gallagher, Rafferty, Huntington, Cunningham.
Watford line-up: Bachmann, Cleverley (c), Pedro (Perica, 81), Masina, Sema (Zinckernagel, 81), Chalobah (Gosling, 73), Cathcart, Hughes, Femenia, Sarr, Sierralta. Subs not used: Elliot, Troost-Ekong, Wilmot, Lazaar, Gray, Hungbo.
Referee: Mr T Harrington