The east Londoners stormed into a two-goal lead before the Dons pulled one back. Tempers frayed in a thrilling finale, but it was Fairlop who scored the game's crucial fourth goal to secure the points.
Fairlop boss Aaron Dias was "far from happy" with the home side's footballing performance - the Dons set up to make it difficult for them to play football today and for the first 25 mins their game-plan was working.
Slowly but surely, Fairlop had more joy going forwards, playing with great patience and maturity. DIas "knew that if they kept trying to play football the goals would come". And how right he was.
Fairlop broke the deadlock when a delicious crossfield ball from Pierce Prince found "pocket rocket" Garfinkle, who joined recently from Premier Division Redbridge Jewish Care, who picked the ball out the air, sold the defender and coolly slotted the ball home.
For the most part it was a really scrappy game and the second goal "should have been enough to send the Dons back to north London with nothing to show for there efforts," but they came out the second half and pressed and supersub Richard Reback managed to bundle the ball home after a goalmouth. Game on.
There were some flashpoints as the game headed into the final 10 minutes but another piece of class from Garfinkle put daylight between the team. He raced down the left flank before slotting the ball across to Hopps, who cooly passed the ball home to send his team-mates and fans wild!
Fairlop boss Aaron Dias told JC Sport: "We always knew it was going to be tough today, especially missing our two star men of recent weeks, James Jaconelli and Jordan Kara.
"What a day! What a result! It was a great day for all players and fans of this wonderful football club.
"Today should once again showed what Fairlop Football Club is all about. Pure grit, determination, passion and a little bit of quality won us that football game.
"There is a lot of football still left to be played but that was a big step towards the title. Confidence is sky high and the boys are more committed than ever, Roll on the quarter-final next Sunday... I wonder what the Danny Caro pre match prediction will be 😉."
Dons boss Brandon Hamme told JC Sport: "It was a disappointing result, but the boys gave it there all and put in a solid display especially in the second half when we looked like we could have got ourselves back in the game.
"We don’t feel too disheartened with some more match fitness under our belt and some returning faces I believe we can give Fairlop a good game once again next time round, and hopefully this time pick up a result."
Hamme described Mill Hill's next game against FC Team as "absolutely huge and season-defining". He went on to say: "We got a result against them last time but they gave us a very good game in the process and we know we will have to be at our best.
"We can’t afford any more slip-ups and I’m confident that we will put the disappointment of Sunday behind us and put in another good performance this weekend."
FAIRLOP: Matthew Berkley, Ryan Cole, Max Freedman, Adam Goldman, Daryl Rubin, Jacob Sanders, Daniel Bean, Bradley Gayer, Pierce Prince, Daniel Rosen, Daniel Garfinkle. Subs: Mitchell Gold, Kane Hopps, Brad Porter
SCORERS: Garfinkle 2, Hopps
DONS: Oli Burchell, Adam Ben-Harosh, Josh Cinna, Sammy Hakimian, Adam Isaacs, Ryan Kramer, Adam Morrow, Harry Moss, Jamie Nagioff, Nick Phillips, Zach Cohen. Subs: Josh Moses, Richard Reback, Jason Weldon