Preston edged into fifth spot by winning this clash against play-off rivals Watford, who are also attempting to reach the play-offs as a departing gift for retiring manager Graham Taylor.
Preston, enjoying their best season for nearly 40 years, gave a league debut to rookie keeper Andrew Lonergan - and the 17-year-old made four crucial second half saves.
Preston had a couple of early chances but everything changed on 24 minutes when Jon Macken was clattered by Alec Chamberlain and Steve Palmer's defensive efforts. Graham Alexander despatched the spot-kick.
The home side's tails were up and they grabbed a second goal after 33 minutes.
Alexander's looping cross was nodded on by Anderson, leaving Macken the simple task of slotting in from close range.
But Watford replied with a stunning goal from Noel-Williams 10 minutes before the interval.
And they levelled after 59 minutes when Peter Kennedy's swinging corner found Robert Page right in the thick of the action, and he stooped to put a header over the line.
But Preston stole the winner exactly a minute later, with Macken collecting his 17th league goal of the season. Rob Edwards' deep cross found Macken ideally placed for his shot which beat Chamberlain in the Watford goal.
Preston: Lonergan, Alexander, Edwards, Murdock, Kidd, McKenna, Anderson (Cresswell 67), Gregan, Rankine, Healy (Cartwright 68), Macken. Subs Not Used: Barry-Murphy, Gunnlaugsson, O'Hanlon. Goals: Alexander 25 pen, Macken 34, 61.
Watford: Chamberlain, Cox, Robinson, Palmer, Page, Nielsen, Mooney, Kennedy (Wooter 81), Vernazza, Noel-Williams, Smith. Subs Not Used: Hyde, Day, Helguson, Panayi. Booked: Page. Goals: Noel-Williams 36, Page 60.
Referee: Tom Jones (Leeds).
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