David Nugent and Paul McKenna struck 12 minutes apart in the second half to deliver a 2-0 win.
It was Nugent’s fourth goal since signing from Bury that January.
The striker celebrated by putting on a bowler hat thrown from the away end, the first Gentry Day having been at Queens Park Rangers a few weeks before.
After the game, PNE boss Billy Davies was rich in his praise of Nugent – then only 19 –for the impact he’d made in stepping up the divisions.
Davies said: “As soon as he got to the club you could see the quality he had.
“I think this is at least the level he can play at.
“We expect big things of him and I think he has the attributes to go right the way to the top. If he keeps his feet on the ground there is no reason why he couldn’t play in the Premier League.
“He is strong, quick and has shown that he can score goals.”
North End had gathered a head of steam under Davies’ leadership in the three or four months before this trip to Watford.
The away form had seen a huge improvement, this a fifth win in the last eight games on the road – they had lost only one of those.
Contrast that to the first 12 away days of the campaign when North End had won one in 12 – first under Craig Brown and then Davies when he took over.
Victory at Watford was a bit of a scrap on a heavy pitch which the Hornets shared with rugby union side Saracens at the time.
The first half was goalless, Richard Cresswell having the best chance with a shot which hit the underside of the bar and bounced down just before the line.
Nugent set up Eddie Lewis but the American winger put his effort wide.
At the other end, Chris Luketti made an excellent block from Johnnie Jackson and then executed a fine sliding tackle on Danny Webber.
PNE made a breakthrough in the 60th minute to the delight of a large travelling contingent.
Hornets defender Neal Ardley, in attempting to put the ball forward, lost it to Callum Davidson.
The left-back’s pass found Nugent who ran into the box and fired low past the keeper.
Off he went to celebrate in front of the Preston fans and a bowler hat was thrown his way, the youngster obliging and putting it on.
In the 72nd minute, North End doubled the advantage.
Chris Sedgwick was fouled to the right of the box and awarded a free-kick.
Graham Alexander took the set-piece and instead of lifting a cross into the middle, the right-back rolled it into the path of McKenna outside the box.
McKenna did the rest, rifling a shot in to the net from 20 yards – not bad for a man playing with stitches in his ankle.
Nugent came off a few minutes after that goal, a ploy which Davies had used a few times – it was a case of building up his fitness steadily.
PNE saw out the game without too many issues although it needed a covering header on the line from Youl Mawene to clear Brynjar Gunnarson’s header.
That chance arose after Davidson and loan keeper Chris Day had got in a tangle.
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