The front man opened the scoring from the spot in the opening stages and by the time the second half was five minutes old, he had completed his treble.
Zenon Stylianides and Luke Amos had both earlier gone close to joining Harrison on the scoresheet, with substitute Ryan Loft converting a late penalty after Savvas Mourgos had pulled a goal back for the Gunners.
It marked our second 4-1 victory over one of our London rivals in the space of four days in the Barclays Under-18 Premier League, having seen off Fulham by the same scoreline at the weekend.
Playing at the Training Centre, we made a positive start in the North London derby, Ismail Azzaoui exchanging passes with Joe Muscatt on the left before surging down the wing and clipping across a low centre which Stylianides stabbed just wide under pressure from Ben Sheaf.
Azzaoui and Muscatt linked up again in the build-up to our opening goal on 17 minutes, the latter heading into the path of the Belgian youth international, who tricked his way into the box and was brought down by Gunners goalkeeper Hugo Keto as he went through. The referee pointed to the spot, with Harrison finding the corner of the net despite Keto diving the right way.
Stylianides steered wide of the near post after getting on the end of a Charlie Owens free-kick on 25 minutes, before we extended our lead four minutes later – Harrison latching onto Muscatt’s throw-in from the left and turning his marker before rifling into the net from a tight angle on the left side of the box.
Harrison might have made it three shortly after the half-hour mark but headed straight at Keto from another Owens set piece, while Josh Da Silva lashed over the bar in one of few openings afforded to Arsenal in the first period.
Christian Maghoma then tested Keto with a header after Azzaoui’s corner was nodded back across goal by Harrison, while Stylianides went closer still when he fired over the bar from eight yards out following Armani Daly’s cross from the right.
Mourgos blazed high over the top at the other end while we very nearly snatched a third goal just before the break, Amos sliding in to meet Muscatt’s ball in and steering towards the far corner – only for Keto to get back across goal and make a save to deny him.
Keto was there again to thwart Azzaoui in a one-on-one situation less than 20 seconds after half-time when the attacker seized on a wayward pass in the Gunners’ defence, but he could do nothing to prevent Harrison completing his treble in the 50th minute – the forward coolly slotting into the far corner after Azzaoui’s low centre from the left wasn’t properly cleared.
The latter cut infield and tested Keto with a 20-yard drive on 56 minutes, while Harry Voss palmed a long-range effort from Sheaf over his own bar at the other end.
That signalled a period of Arsenal pressure, interrupted only when Loft was denied by Keto from point-blank range after latching onto Daly’s deflected cross just after the hour mark.
Substitute Chris Paul was forced to intervene as Sheaf tried to play Da Silva through on goal, while Voss caught a 22-yard shot from the latter as the Gunners tried to get back into the game.
Their efforts were rewarded on 64 minutes when Mourgos wriggled free in the box and struck low into the corner to pull a goal back, but that was as good as it got for the visitors as we proceeded to re-establish our hold on the game.
A route-one clearance from Voss outfoxed Arsenal centre-half Kris Da Graca and allowed Loft to go through one-on-one with Keto – the keeper managing to make a save – before Azzaoui raced down the left and produced another stop from the visiting number one.
Loft nodded wide from Azzaoui’s cross before finally hitting the back of the net with 78 minutes gone. Daly sent the front man powering forward down the right channel but he was upended by Harry Donovan as he entered the 18-yard box and a penalty was awarded. Loft dusted himself down to strike low to the keeper’s right and restore our three-goal cushion.
We saw out the remainder of the game efficiently – Amos having to concede a corner two minutes from time to prevent Arsenal from applying the finishing touch to a late attack – thus completing a league double over our North London rivals, following on from our 2-0 away win back in October.
Spurs: Voss, Ross, Muscatt, Owens, Maghoma (Paul 58), Walkes, Daly, Amos, Harrison, Stylianides (Loft 58), Azzaoui. Substitutes (not used): Hayford, Glover (GK).