The midfielder latched onto a cross from the energetic Kyle Walker-Peters 11 minutes into the second half, while an acrobatic save from goalkeeper Liam Priestley in stoppage time ensured we ran out with all three points in the Barclays Under-18 Premier League clash.
Both sides had chances in the first period, Liverpool's best arriving just five minutes in when Tom Brewitt headed wide after getting on the end of Alex O'Hanlon's cross from the right.
Cy Goddard saw his free-kick blocked by the wall at the other end after Matt Virtue brought him down on the edge of the box, while O'Hanlon bent a shot just beyond the far post after capitalising on a slip by Lloyd Ross with 11 minutes on the watch.
The end-to-end nature of the game continued when Kane Vincent-Young's left-wing cross was nudged behind by Liverpool goalkeeper Owen Wheeler with Kyle Walker-Peters arriving at the back post.
Walker-Peters was lively down the right side throughout and it was he who sent in a 21st minute cross which bounced just in front of Pritchard to stop the midfielder from getting a clean shot away from a central position.
Filip Lesniak dragged well wide for us shortly afterwards, while Liverpool's O'Hanlon fired off a shot which was comfortable for goalkeeper Priestley.
Striker Daniel Akindayini was in action at both ends in the moments that followed. He was first called on for his defensive skills on 36 minutes, being forced to turn Ryan Kent's free kick behind for a corner at the far post, before bearing down on goal at the other end, only to be denied by a last-ditch tackle from Dan Cleary.
Kent was to the fore again just before half-time. He was played in behind our defence with Priestley making a fine save from point-blank range - but an early linesman's flag meant it wouldn't have counted anyway.
Pritchard almost broke the deadlock 30 seconds after the interval, chipping the ball just over the bar from the left side of the box with the goalkeeper beaten.
But he made no mistake on 56 minutes - burying Walker-Peters' low cross from the right at the far post, after the ball ran just beyond Akindayini at the other upright.
Liverpool went close on 72 minutes when Kent siezed possession in midfield and fed Sheyi Ojo down the right channel, the attacker cutting inside and curling a left-foot shot towards goal. However, it lacked power and was quickly pounced on by Priestley.
Walker-Peters almost doubled our lead a minute later, his low shot just being touched beyond the far post by the outstretched fingertips of sprawling stopper Wheeler after substitute Shayon Harrison sent him charging forward.
Liverpool's Nathan Burke then volleyed over the top after a neat passing move from the hosts, before Harrison produced a low stop from Wheeler after leading a break forward.
The hosts might have levelled a minute into stoppage time when Dharius Waldron set up Connor Randall to let fly from inside the 18-yard box but a fantastic save from Priestley, springing to his right, saw the ball palmed away to ensure we held onto our slender advantage.
Spurs: Priestley, Walker-Peters, Vincent-Young, Lesniak, Maghoma, Carter-Vickers, Goddard (Daly 82), Walkes, Akindayini, Ross (Harrison 46), Pritchard (Campbell-Young 67). Subs (not used): Georgiou, Whiteman.